The only Clevedon appears to be on the West coast of North Somerset in which case it is a good distance away - probably in excess of 100 miles.
I would not have thought that labourers would have moved large distances that far back - on the other hand I cannot find any mention in my records of a Thomas being born around 1793/4 in the Cuddington/Long Crendon/Chearsley area.
It is some years since I last did any research into my family in that area and I might well take a trip down to Aylesbury (where the records office for Buckinghamshire is)sometime in the relatively near future. If I do I'll see if they have the parish register for Chearsley and see what I can turn up.
In the menatime if you need any more assistance please let me know.