I stand to be corrected but I believe the only place to sail I.C. in Nottingham is at Colwick Park with the Nottm Model Boat Club.
Yep - that's my best information too, Colin. It isn't against any national statute to run an I/C boat but local authorities have by-laws prohibiting them from most waters. The other law to consider is the frequency; you can use 27Mhz, 40 Mhz or 2.4Gb (there's also an old UHF frequency - was it 475?), but NOT 35Mhz, which is strictly only for aircraft.
As regards insurance, a 23cc strimmer engine whirling a prop could do a lot of damage if it hit someone; you can't stop it just by letting go of the Tx stick like you can with an electric-powered model. In these days of instant litigation it would only be sensible to take out some third-party insurance. Like the man said, let's be careful out there.
FLJ