Wow - thanks for the incredibly helpful answers. I really had no idea how to start looking, so the advice was great. But Spanish's suggestions are brilliant - having looked quite closely, the Embraer 170 looks a likely candidate.

I've now got some pictures of the inside and thought I'd post them up to see if the codes mean anything to anyone. I think they might!



The 170 on here makes me think Spanish is right... .


And this!

thanks again, all.