Robin, hope you're well and back on the bike soon. The amount of craters (potholes doesn't do justice to most of the chucks that seem to be missing from most of Surrey's lanes at the moment) is alarming. It seems worse week by week.
I remember from last year we did the normal CR route to Newdigate and then swung right to join the Box Hill return run route. We used Ryka's as a cafe but it might be better to use the one at the top of Box, although more expensive as climbing up the hill straight after a rest and grub wasn't the easiest.
The actual route worked well though, but need to watch for potholes on the first stretch of road off the top of Box.
Re the sprint I tried to moot a lead out a while ago but sadly it seemed short on takers. Without moving the sprint point to a straighter road I think that's the best bet. All it would need is someone to forgo a sprint that week to wind the pace up and string riders out. It's only that no-one wants to be on the front that causes the bunching.
All it would need is an agreement to rotate lead out man/woman from week to week. It would be fair as people would be able to sprint if they wanted at least 7 out of 8 weeks.
No cafe this coming Saturday as it's closed, but I would be happy to lead out after that.