You are wasting your time, really. It will be horribly complex to convert all the events/datas/etc from England to GB.
Instead, you could change the name of the 'ENG' tag to 'Great Britain' instead of 'England'.
Go into config/text and find the following lies:
Code:
###########################################;;;;;;;;;;;1123
###### NAMES OF COUNTRIES & AREAS #####;;;;;;;;;;;1124
###########################################;;;;;;;;;;;1125
# IMPORTANT! COUNTRY NAMES MAY NOT BE TOO LONG;;;;;;;;;;;1126
#;;;;;;;;;;;1127
MIN;(Undefined Nation);;;;;;;;;;1128
[B]ENG;England;;;;;;;;;;1129[/B]
FRA;France;;;;;;;;;;1130
HAB;Austria;;;;;;;;;;1131
HOL;Netherlands;;;;;;;;;;1132
POR;Portugal;;;;;;;;;;1133
Then, change 'England' to 'Great Britain'. Of course it will alway apear as 'Great Britain' but change it only for the game you want.
Don't forget to make a backup of your original file.
And btw it is the wrong place to ask this.