Beaten from low growing scrub on chalk grassland.
No interactions present.
it's an ichneumonid wasp, family Ichneumonidae, subfamily Pimplinae, tribe Polysphinctini, this tribe specialises in ectoparasitism of live adult spiders. The spider is doomed, but if you keep it the larva will make a cocoon from which a wasp will eventually emerge.
Many thanks - I'll try it and see....
Lat/Lng: 51.3053, -0.1788
OS grid ref: TQ270578
Part of the Chipstead Downs SSSI