Ladies,
The sportive on May 8th organised by Action Medical Research is interesting because it is for ladies only.
Start/finish is near Midhurst with 100 and 50km routes and both seem reasonably challenging. It will be led out by Davina McCall.
Here'e the link>http://www.action.org.uk/davinas_diva100
Downside - it is a charity ride so you will need sponsorship or a deepish pocket (purse??).
Upside - Action Medical sportives are the best organised in my (admittedly limited) experience and the entry fee includes:
chip timing
fully signed route
lunch stop
serviced refreshment stops
NEG motor marshals
full paramedic cover
bike mechanics
post event massage
ride memento
event photographer
They have great marshals too - one of which will be me (not sure how I will cope with 700 female cyclists (cyclistes?) mind - one has to take the rough with the smooth I guess!).