Whereabouts in Oxford? I live near Witney and was a member of the Oxford MBC for a few years, but issues with parking, algae, and aggressive swans spoilt it. I know of several people who sail there who have had boats damaged or even destroyed by the swans. One of mine was badly damaged.
I am now a member of the Mid Thames Model Boats Club who have access to a large lake south of Reading with only a couple of swans, who keep well out of our way. Car parking is a few metres from the lakeside, there are tables to set up on, and a rescue boat should a model get stuck out of reach. It's a very friendly club.
It's over an hour's drive each way for me, but it is worth the effort.