Philodromus praedatus (Philodromidae).
Male. Very similar looking to 2 of the other Philodromus I've found - P. aureolus (which I found today as well) and P. cespitum. ID based on palps, especially tibial projections (as in sketch on photo) which match pretty closely to the photos on Spiderling.de and illustrations in Roberts' book.
Found resting on new fence at heath/wood edge. Bricket Wood Common, Hertfordshire, 17th June 2012.
Jorgen Lissner - male
Spiderling.de - male palps