Hello and thank you for the replies to my first post.
In the end I did ask my marina if they would make some allowances and I received a very satisfactory response. They will charge me at the annual rate but on a monthly basis. This has reduced my costs by about a third whilst leaving me free to leave the marina without penalty once the situation will allow it. I am very glad I asked.
It does appear that many marinas are now giving some concession to owners, some as price reductions and some as contract extensions free of charge.
Thank you for the point about the insurance, I will be checking mine.