I recently started to study differences between american and british English. It's interesting and I now understand why I was taught something at scool (british) but people use something different on the net (for the most part, american), etc...
I think the traditional process for games developed in Japan is to fist translate them in English by american people and release the game in north america, and finally, if the game is really sucessful, port it to PAL, but all the american english from the USA version is kept. If the game is very sucessful and if the company has the means then more locals translations are made (german, french, spanish, italian, ...) by people from those respective countries. More often than not, those translations are made from the (american) english version and therefore suffers from double-translation problems. However big companies now tranlate games direcly from japanese, which is typically better.
I wonder if any games were re-translated from japanese by British people for the PAL release, or if games that were released in PAL territories but not in north america (not many games - Terranigma comes to mind) were translated by British people and uses British english.
There should also be games developed by British comanies, but I admit I play exclusively games made by Japanese companies so I don't know much about it. At least Rare is located in Great Britain. Does Battletoads uses British english ? I'm not skilled enough to see the difference.