Lens hire caveat for Fixation:
If you've never hired from them before, they require you to lodge a deposit equalling the retail value of the lens (or other kit) with them... so if you fancy hiring a nice 100-400mm
L, then you better have the rental fee
plus another £1000 free space on your credit card.
Also the fees exclude VAT and the 10% hire insurance premium.
If you don't mind renting Sigma lenses instead, try
Hireacamera.com - much better prices and hire terms.