M & S undies, for sure. Boots Botanics Energizing Shower Gel with Butcher's Broom, if they still do it (Target doesn't seem to have that one) I would be tempted to rush out and buy loads of designer cushions and fabric that you don't see in the US. But then I would also have to ship back all that stuff my mum lugged over from the States, against my protestations.
When I went back after my first year in the UK I had bought a sheepskin coat, woolies, loads of tea towels that would remind me of places I'd seen, a Welsh tapestry bed spread from Habitat (but ended up leaving that with a friend -- now DH!), a Welsh tapestry tea cozy, Aqua Skips shoes (!) and not a lot else. But I ended up back in Leeds within a year