I'm not sure if you're saying for you the Thistle is walkable, which it is definitely (25mins according to google). I've done it a couple of times.
You do have to negotiate the "no pedestrians" bus link by the roundabout though...
If you're happy with that walk you have the Premier Inn T5 opposite the Thistle and then the Sheraton Heathrow Hotel then behind that on the other side of the by-pass.