Harrods, Selfridges, Harvey Nichols, Dover street market, Matches and Browns have celine bags. They all have different range of bags.
Recently I made an online purchase (not a bag though) via department feminine, which is based in France. They also have a few bags you can take a look. They were super nice.
Most of the stores don't seem to have pre-fall delivery yet. So most stores might not have enough bags left. I'm waiting for the prefall to arrive, and I think I still have to wait about a month or so..... HTH!