Got a reply.
"We can indeed offer a group shootout.
The price for 10+ is £35.00 all in. This covers 2wd and 4wd. You will get
printouts of Fly hp and torque, wheel hp, and afr/boost where applicable. We
dont tend to use the wideband on diesels as this greatly shortens the probe
life".
Maybe if enough people show an interest and intention to participate on the RR by posting in here, I'll get a provisional date sorted.