I don't see the point in me paying £5000 for a CPL that i am never going to advance from
Depends how you look at it. You'll probably spend £10k putting an FI(A) on your licence. That might be worth say 50-75 hours-worth of PPL flying to you, depending on what/where you fly. So until you achieve 50-75 hours-worth of trial lessons or check flights or whatever, you're out of pocket.
200-300 hours-worth of instruction (depending on the rate of course) will pay for your CPL.
I started down the same path like you about 5 years ago. I only wanted to put an FI(A) on my PPL to help increase utilisation of aeroplanes in which I was a shareholder, and which were suffering from lack of instructors. 5 years later? CPL+MEP+IR+FI - once that ball starts rolling it's awfully difficult to stop
