What happens when you give up C1,D1 licences at 77

Pippin

I have a C1,D1 driving licence but have sold my large motorhome and would like to stop paying for the 3 yearly medical, but if I do will the licence revert to B+E which I had or to a B only.   If its the B only can I tow a small caravan?    Took the test
in 1957