The data supplied by RTN11 a few posts back seems pretty accurate to me. You can expect to earn £20/hour and to get about 50 hours per month (averaged over the year), working six days a week. That comes out at £12k/year working six days/week - so £6k working 3 days/week and £4k/year working 2 days/week. From which you will need to pay tax, self employed NI contributions, travel costs, uniform etc.
To get there from where you are will cost you a minimum of £30k for flight training and hour building. CPL ground school plus sitting the exams (have to be done in Gatwick) will easily add another £3k.
Then you need to find a job! There seem to be more newly qualified FIs out there than there are openings, judging by the steady stream of hopefuls who turn up at my school. You really need contacts to get started.
Sorry if you don't like the numbers, but that's just is the way it is.