You are assuming
A - I live that long
B - I have not moved home.
Would you give someone £200 now if they promised to find you in 25 years time and pay it back?
Kaf, no offence meant, I'd be just as annoyed as you, was just trying to cheer you up by putting a silver lining on it for you.
Also, it won't be £200 in 25 years, probably double or triple, depending on FITs rates and leccy bill. Of course in real terms, probably about £200.
My installation was 7 weeks ago, and apart from an email from EDF confirming they are waiting for OFGEM, nothing yet. So if there is any problem accepting my original meter reading then I may be in a similar boat.
Still, you've got to smile haven't you.

Martyn.