RTN11, thank you for your detailed reply!
I've never really seen the appeal of flying airlines, though I see the monetary appeal of being an airline captain. I'm here for the flying, but as I'm too poor to be paying for it all out of my pocket, anything that will dampen the financial impact would be a great help. I can pay for an hour or so of flying, but if I can be paid to do so, either by flight instruction or by hauling freight or doing some job, that would be win-win as far as I'm concerned. The reason I'm looking at FI(A) is because it seems the most likely way I can get some work.
At this point, I'd like to say I'm not here to be a vampire on students, draining them of their time and money to pad my logbook. I enjoy teaching and do it at my current work and on some of my hobbies as well. I find it enjoyable being able to show others how what I do is important, fun, and interesting.
From what I've learned so far, it seems that my path would be PPL -> Night rating -> CPL -> IR -> Instructor -> Multi but I wonder if I should do CPL -> Instructor instead? Would my flight school be able to help me out with estimating the costs for either route?
I understand the freelance bit as well as the uncertain hours, that is why I am hesitant to leave my stable job for aviation... and that is why at this point, anything I do with aviation will always be second-priority to that which puts food on the table and a roof over my family's heads. However, is £15K the average for a FI(A)?
I'll be honest and say that I can't imagine anyone getting by with £15K per year, not unless that person is single and lives with his parents.