It is the bee Colletes hederae, a species that was first seen in the UK in 2001, and whose spread is being monitored by the Bee, Wasp and Ant Recording Scheme (BWARS). They are interested in studying the progress of this attractive bee as it colonises the UK.
They can also be observed on bare ground where they make their nests. With broad pale bands on the abdomen this is the only solitary bee that is likely to be flying now, so identification is not too problematical, if you find one foraging on ivy.
It seems to be getting quite well established in southern England and is spreading inland in places, but records in the RX area would be useful. We know it occurs in Hastings and at Pett but is it elsewhere? For more information on this insect, including details of where to send any records if you have seen one (ideally sending a photographic record of the insect) click here
Thanks to Ian Hunter for use of the above photograph.