I'm going to add something from experience here.
Firstly the Escort GTI is a badly named car, it isn't a GTI in performance terms at all.
But my girlfriend now owns the GTI my Brother-In-Law bought new and it has been a good car tbh.
They do come as std with 115 bhp, I have fitted a filter and Magnex exhaust to the car and it has been RR'd twice at 138bhp! Admittedly I am very fussy with maintenance. There have been no major problems outwith normal servicing except for it needed a new fuel tank last year and I can see it needing a clutch soon as the release bearing has begun to get noisey (now on 97k and original clutch).
Anyway, I like it, not a bad looking car and if you think they were £14k IIRC when new it's not a bad deal.
But IMO a 1.8 Focus would be a better car, the GTI carries a high insurance due to the badge it doesn't live up to. Fuel consumption is fine- mid 30's easily. A mk2 Mondeo is a bargain, so much kit for the money and probably is better built, but does have the image of an older owner. (I have owned one - an ST200)
It's your money, if you like it, buy it!