Hi Ruairi, how is our detective work coming along, have discovered the Coltrane name in America is also a derivitave of the Culrain ...Coleraine line (on an ancestry blog) if that is true we have 3 famous Jazz Banders in our extended family 1 in America 1 in Gasgow 1 in Aus . if you are having difficulties, you may be able to suggest the name of some Ancestry official,  who may have  a scholastic background,particularly of the Area, whom, we may be able to pay for any out of pocket expenses + some fee for time spent looking, including yourself, Ruairi....and if you are successful in the linkage a great gift will....what would that old Jacobite O'Cahan, deem appropriate, it begins with a FEAST

Best of IRISH luck.

Tom