YC,
I work at National Grid and we are frequently looking for good technical staff and currently have a few opportunities knocking around. It'd be worth checking out our
technical training programme either to give some serious consideration (not necessarily too late yet at 25!) or just to help you calibrate your expectations/aspirations. Compare with the graduate programme too, although that's less vocational/hands-on and more general business focussed (think CEng rather than IEng initially). A lot of our upcoming work is associated with connection of new generation, including offshore wind and new nuclear, so lots of potential for coastal proximity!
Hope that doesn't sound like a sales pitch - I am an Engineer by background (Leeds grad too, but next door from Elec Eng). Just wanted to give you something to consider and compare against - big corporate context if you like. Life in a big organisation isn't perfect but it can be a great development and foundation environment. Happy to bounce some PMs for further advice if it helps.
Alternatively, what are the odds of you being able to take over your current company in a few years and keep it going when the "old guard" retires, assuming they won't just wind it up and leave you all in the lurch. MD of a technical niche SME at 30 isn't a bad career ambition and would possibly tip the balance of your remuneration significantly in the above average direction!