Numbers are ideal, and I'd think carefully on if there is a metric you can tie to a data point, but it doesn't have to be all about numbers. Example: maybe you streamlined a common app flow making it significantly easier for users to accomplish a task, or implemented accessibility best practices across your product making it usable by a wider range of people. Both of these have more pop if there is a statistic you can cite with them, but even without they speak to impact not just "worked on Python web application".

If you don't have specific data, you can still frame your work in a way that is more compelling than, "I can code in Python and I worked at XYZ company for 3 years." Whatever value you were adding, put that first, even if it's just "built new products that increased company's sales and helped expand to X new markets."

I have £19m to £75m revenue in approx 20 months bootstrapped start-up CTO on my CV.

In the UK market folks aren't particularly receptive to that sort of thing.

In that case, I wonder if that makes you seem overqualified?

I think it's a combination of the market and assumptions.

- Some think I'm no longer technical enough because I've done managerial stuff, despite recent work being hands on.

- Some think I'm not managerial enough because I still do technical stuff.

- Some think I've somehow failed because the specific role was only ~20 months ( it was actually equity shenanigans )

- Some think I'm too senior and won't stick around ( despite the role being top of the market pay wise )

Mostly, I don't really know, because when going through the front door, they typically don't respond, and in actual fact the only leads I get are the ones that contact me.

But I think our specific culture focuses on reasons to say no, rather than reasons to say yes, and the current market only helps compound this, even if the outcome is worse.

Of course, I might just be shit, but they also likely don't know that by not speaking with me. :)