Friends of mine live between Zurich and London. Does anybody have any ideas for this couple who wants to spend one week every month or 2 in London in terms of nice and inexpensive accomodation close to Chelsea, Kensington, Nottinghill, Knightsbridge areas:

- suggestions of hotels that give special deals in long term
- is there a way to rent an apartment or do some kind of time share?
- nice B&B

any suggestions of what can be done would be welcome. They need a nice clean comfortable quiet place with privacy where they can stay on regular basis at a reasonable cost wihtout having to commit themselves for a long lease