I don't live there. But I heard it is not a good area, a colleague calls it the armpit of the south. There are some nearby towns that are much nicer. You might want to consider those instead. I don't think there are chinese supermarket there, at least no big ones. But you can go down A1 and get down to Oriental City in half an hour

p.s. i am applying for a job at GSK at Stevenage too