>>>>I have discovered that it has Pictish origins
Really? Reaney & Wilson's Dictionary of English Surnames (which is a standard reference work) gives the first recorded incidence of the name as John & William Bani, mentioned in the Rotuli Hundredorum for Buckinghamshire in 1279. The same source also mentions Agnes & Alice Bonye, with Reaney & Wilson linking all of the following surnames to the Old English word (bãn) for 'bones' (which was probably a nickname):
Baney, Boney, Bones, Bain, Baine, Baines, Bains, Baynes, Bayns.
No Picts there!