Board-Level Strategic Adviser · Sum8 · Cardiff, UK · Trusted by CF Houses, PE & Lawyers
Leighton Humphreys
Leighton Humphreys
Founder, Sum8 · View card →

The financial discipline
of a CFO. The instincts
of a CEO.

Shaped by every challenge along the way.

Available on a fractional basis — typically 1–4 days a month.

I work with founders, boards and investors at the moments that actually define a business — growth that needs discipline, cash that's running out, a fundraise that has to land, or a business that needs turning around. Engaged around what you need — without the overhead of a full-time hire.

I also work alongside corporate finance houses, PE investors, lawyers and professional advisers — getting businesses financially and operationally ready for the point where those relationships make sense. The right adviser at the right time. I help businesses get there.

Book a Discovery Call What I Do
What I Do

Four areas.
Complete focus.

Not a broad consultancy. Four specific areas where 25 years of board-level experience makes a real difference.

01
Making Sense of the Numbers
Most businesses have data. Few have genuine clarity. I translate complex financial positions into decisions — identifying what's really driving performance, where value is being lost, and what needs to change.
  • Numbers that don't add up — or just don't make sense
  • Margin and cash performance diverging from expectations
  • Board and management seeing different pictures
  • A business at a decision point that needs clear financial ground
02
Growth & Scaling
Growth that outpaces infrastructure is just risk wearing an optimistic face. I build the financial discipline, controls and decision-making frameworks that let businesses scale without losing control of what matters.
  • Revenue growing but cash and margins not following
  • Finance function not keeping up with the business
  • Preparing to scale and needing board-level financial leadership
  • Investor or lender visibility becoming a concern
03
Turnaround & Stabilisation
When a business is under real pressure — cash running out, key person departed, investor confidence wavering — the priority is clarity and speed. I step in, assess the full picture fast, and build the plan. No panic. No platitudes.
  • Cash burn becoming unsustainable
  • Management change creating a vacuum
  • Investors or lenders losing confidence in the numbers
  • A business that needs stabilising before it can move forward
04
Supporting a Successful Fundraise or Exit
I've raised money and I've done the diligence on businesses being acquired. I know what investors find, what gets challenged, and what makes the difference between a process that completes and one that doesn't.
  • Preparing for a funding round — seed, Series A, or beyond
  • Building a financial model and business plan to withstand scrutiny
  • Approaching a sale and wanting to control the narrative
  • Due diligence on an acquisition target or investment opportunity
About
ACA · Big 4
PwC Transaction Services — financial due diligence & corporate finance
CEO · CFO · COO
All three seats. Real accountability at each.
25+ Years
Board-level across multiple sectors and situations
Scaled 4×
NHS-backed MedTech — stabilised, funded and scaled
500 Stores
Finance Director, major UK retail group

Every seat.
Every kind of situation.

"I've been the CEO, the CFO and the COO — and the adviser parachuted in when things went wrong. Sharp thinking, complete integrity, sleeves rolled up."

Trained at PricewaterhouseCoopers in Transaction Services — financial due diligence and corporate finance for corporate and PE clients. Since then: a financial recovery role, an acquisition I led and then ran as MD, Finance Director at a major UK retailer across three brands and 500 stores, and most recently CEO, CFO and COO of an NHS-backed MedTech business — brought in by investors to stabilise it and scale it 4×.

Every recommendation I make is backed by a decision I've actually had to live with — and the consequences that followed. That's not a credential. It's a different kind of help.

Healthcare & MedTech
Retail & Consumer
Energy
Automotive
Start-ups & Scale-ups
Investor-Backed Businesses
The Difference

Some advisers work
from the playbook.
I've lived it.

There's a difference between recommending a course of action and having been the person accountable for it.

✓
Made the call — and lived with itNot just recommended it. Every engagement draws on decisions I've actually had to make and consequences I've had to manage.
✓
Run turnarounds, fundraises and acquisitionsAs the person accountable — not the person advising from the side.
✓
Stays through the difficult partThat's usually where I'm most useful — and where most advisers step back.
✓
You deal with me — throughoutNo account managers. No junior handoffs. Leighton, from first call to final delivery.
For Investors & Lenders

Independent visibility.
Not filtered through management.

For development banks, PE houses, banks and institutional stakeholders with portfolio companies that need hands-on support. CEO, CFO and COO experience means the assessment is never just financial — I look at the full picture and tell you what you're dealing with.

  • Full CEO-level due diligence — business, team, operations and numbers
  • Interim board support after management change — stability while you find the right permanent solution
  • Independent reporting direct to investors — board packs, covenants, KPIs
  • Short and long-term portfolio company support across all four service areas — typically one to four days a month
For Corporate Finance Houses, PE & Professional Advisers

A trusted pair of hands
before you're in the picture.

I don't do corporate finance. That's deliberate. My focus is businesses that are too early for corporate finance — where the fee structures don't yet make sense, but where the groundwork matters enormously.

I work with businesses to get them ready — financially, operationally and strategically — so that when the time comes to appoint a corporate finance adviser, the process is faster, the story is cleaner, and the outcome is better. I actively look to introduce businesses to the right CF house, PE relationship or legal adviser at the right point in their journey.

If you work with businesses that aren't quite ready for you yet — I'm a natural fit for that gap, and a source of warm introductions when they are.

  • Corporate finance houses — referral relationship for pre-mandate work
  • PE and growth investors — portfolio and pipeline company readiness
  • Lawyers and professional advisers — trusted referral for clients needing financial leadership

"He doesn't just report the numbers, he uses them to give founders a clear set of actions and the confidence to take them. I'll keep sending Leighton clients because he consistently turns financial complexity into decisions people can actually act on."

LUCY · The Structurist, Inc — Referral Partner
Results
Start the Conversation

45 minutes.
No pitch. No pressure.

A straightforward conversation about what you're dealing with. If I can help, I'll tell you how. If I can't, I'll tell you that too.

How we work together is shaped around what you need — a specific project, or ongoing fractional support typically one to four days a month. Board-level impact without the cost of a full-time hire. The discovery call is where we work that out.

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