Hello
Regarding your request on the Kennaday family at Bewcastle.
I did check out the original church records today, but the early records are practically unreadable, although I did see your Leonard's baptism registerd on the 4th March 1759, as you stated, and father as Thomas Kennaday.
I did find,
Robert and John Kennaday, sons, baptised 21 October 1822, parents stated as Leonard Kennedy and Jane Kennaday, Nee Dodgson. Also noted the marriage dated as 26 March 1823, at Bewcastle, lives at Cleughside, Cumberland. Witness to the wedding, John Elliott and Margaret Armstrong.
Also, William baptised 28 June 1823 , parents Leonard Kennaday and Jane Kennaday, Nee Rae, lived at Roantrees, Cumberland.
The actual church records are easier to read after 1813 though they do begin at 1788.
I hope this helps and fits in somewhere.
Merry Christmas
Regards
Louise