I am still searching for Walter. I found the Church of Ireland BMD records for Bere Island from 1787 which includes British military personnel. Unfortunately I found no reference to Walter but I took all the regimental details I could find. Some of the records included the regiment of those listed as grooms/fathers etc.
1st,2nd and 3rd Garrison Battalion
Tipperary Militia, Wicklow militia and Leitrim Militia
Royal Veteran Battalion
4th, 6th, 8th,9th, 18th, 19th,24th, 34th,41st,51st, and 70th.
Apparently I need to narrow this down in order to get a professional search done. Any ideas anyone ???