Hello cousin!
I am not sure how Henry Lock of South Cerney, Gloucestershire 1770's is related to Richard Lock of
Ampney Crucis, Gloucestershire 1690's, but DNA testing a Henry Lock male descendant and a Richard Lock male descendant, proves we are a 65/67 DNA match, meaning Richard and Henry are some how related.
Richard Lock and wife Mary Eldridge may have also spent time in Islip, Oxfordshire 1690's.
I find christening records for their children in both places, which according to the map, Islip isn't all that far from Ampney Crucis, and South Cerney isn't all that far from either place.
It is interesting that you mentioned Fiddle playing. My elders are always asking me if I have ever located who has possesion of the family fiddles! My direct lineage apparently had several fiddle players and no one seems to know where the family fiddles are now.
One of my closer cousins, was a steel guitar player back in the 1940's -50's and made it on the radio with his band. So music was a part of my family years ago.
But unlike Henry Lock, Richard Lock migrated to the USA by 1728.