The Spider and the Fly (well Wasp actually)

At Samphire Hoe a couple of weeks ago, one of the group spotted a spider and insect crawling along the sea wall.

Spider-hunting Wasp and Prey

Once I got the photo on the laptop, I realised that the insect was actually pulling the spider along, and after a conversation with the ever-knowledgable Malcolm,  we are now a step nearer to an ID.   The spider looks like an Orb-web, possibly Garden spider, and the insect is a Spider-hunting Wasp Pompilidae - no idea of which though!

Any suggestions welcome