Tuesday 26 May 2015 3.02pm
I use Zipcar occasionally and find it useful as their cars & vans are all over London. You can cancel up to 3-4 hours in advance of your booking with no fee.
However, sometimes they change your reservation with 24 hours notice so you have to keep an eye on your email. For example, I had booked the Zipcar Golf on Bermondsey Street
on Sunday 17 May, but received an email on Saturday 16 May saying that this car was unavailable and they had booked me the Golf at Druid Street
instead. Good job I checked!