brideseeking blush - hmm never considered addison lee, will have a look. been researching white taxis. not sure about the minimum hire time but i found these two sites:
http://www.thelondoncabcompany.com/wedding_taxis.asp
http://www.weddingtaxis.co.uk/index.htm
will contact them today
beccy - white taxi sounds fab. very London! the Petersham didn't have an available suite so am going with the Richmond Gate Hotel. they're being poo about the early check in though :(
GB - oooh limo might be a fun idea, could get us all to go together, drink some champagne on the way etc. have a suspicion it might be pretty pricey
sigh the hunt continues. but at least now i know it isn't worth getting a proper wedding car, lots of other decent options xx