Regarding your point about money: yes, it is expensive here, but you’re seriously exaggerating as to *how* expensive it is.
As for language: Gateshead is indeed 100% English. Yiddish is almost non-existent here – barely used by anyone. That said, quite a few people do know it (at least somewhat), but it just isn’t used very much. The daily language is English.
The accent first of all has nothing to do with Northampton (that’s very far away from here), and further, it applies to the non-Jews only, really. The frum people speak normal, proper, neat English. As for the non-Jews, if you speak with them, they’re perfectly understandable, I haven’t had any trouble understanding what they say. (And I’m not even a native English speaker at all.)
Gateshead has two major negative points: 1) the weather, and 2) the local non-Jewish population. Regarding point 1, that’s obvious. Regarding point 2, the problems here are mostly with the native white British population – not the immigrants. The Jewish area is surrounded by not such very nice non-Jewish areas. However, it is generally safe (especially inside the Jewish area) and any problems are usually minor, not really serious. I think France, Belgium or London are much more dangerous. That said, I’m glad the sems have a curfew (22:00 I think).
Positive points: it’s a relatively small but very tight kehilla. Now obviously I don’t know much about the sems, but I do know that the new sem has a reputation for being very international, as DPEST wrote above. Also, I do know they do take the students on trips, and the area around here is really nice. There are also plenty of shopping opportunities around (there is a bus to Newcastle right next to the sem every 10 minutes, and there is also another bus to a giant shopping center called the Metrocentre right next to the sem as well).
The kehilla is one of the best I’ve ever seen, and as many people say, it is the only remaining real European kehilla. The only places which would come close would be Kiryas Joel and New Square, I suppose. Also, it’s almost 100% Litvish/Yekkish.