Somewhere on your councils website should be a list of byelaws, including, or not, types of model boat allowed.
Carrying either your own, or a club's, insurance is a good idea, and membership of a club affiliated to your regional engineering association and having a certified boiler tester is good as well, being a way to having a test certificate and access to a valid set of operation documents. This last is important so that you can show that you are behaving in a safe manner to a plod or council official.
However, if the water is populated by a bunch of selfish bodies who have the capability and desire to cause you grief however right you can prove yourself to be, the only answer is distance.
One of the things that caused the demise of the classic boat rallys (full size) on my local lake (among others) was a report from a toxic old biddy who was "walking in the park with her grand-daughter, and they saw a speeding boat hit a duckling", the report repeated for three years.