The Staines branch of Gap is quite a large one and is over two floors, so there's lots of choice. Staff tend to greet you as you come through the door, which I suppose is intended to make you feel welcome, but in fact I always find it intimidating and false.
The children's wear in particular is nice and is reasonably priced. The mens and womenswear is less impressive and my particular bugbear is that they produce relatively large sizes, but don't order very many larger items for each store, meaning that we fatties are often disappointed.
Once you get past the initial awkward American-style greeting, the staff are generally friendly and helpful. read more