On my 21 (No 30) the winches are bolted straight on to the top of the coaming. The port one works fine but the starboard one used to jam due to the lead from the genoa car and the fact that the winches are a bit wide for the top of the coaming leaving a "nip". It may be that your previous owner found another solution but used unsuitable material.
I stuck a wedge outboard of the winch to guide the sheet up over the bell of the winch so it didn't get stuck. I'll take a pic tomorrow when the tide comes in and email it to you. Don't think this system allows pics.
Geoff
Geoff Harwood