I funded it the same way as most people, 1/3 savings, 1/3 loan, 1/3 parents (loan
)
With the added benefit of around a 10-15% employee discount for doing it with the school I was working for.
The wages aren't that bad, you just have to get used to squireling money away. At the peak of my career I earned around £2k gross two or three months in a row, and as a freelance instructor you ultimately pay less tax on that than a direct employee would. At it's worst I earned around £200 in one month when we were closed for half a month due to snow.
Overall gross around £12-15k I would imagine. Maybe a bit more once you can instruct night and IMC.