[ANSTHRLD] Locative bynames in late-period Scotland?

[John Atkinson]

So there's a gentle who's been using William MacKay since some time in
the 1990s, but never bothered to register it.  Not a problem
registering it now, except that some gentle in the East went and
registered his name, William MacKay, in 2002.

Ooops.

So the client asks if he can be William MacKay of Ayr, that being the
town his persona hails from.

Documenting that Ayr is in fact the Period form of Ayr doesn't seem to
be the hurdle.  The hurdle is documenting that in late period Lowland
Scots, that would be the correct way to distinguish William MacKay
from Ayr rather than the William MacKay who has lived here all his
life.  I've been dinking around all the Scottish name website I can
find, and I cannot find documentation of this name pattern.

Ioannes
-- 
"Thousands of Sarmatians, Thousands of Franks, we've slain them again
and again.  We're looking for thousands of Persians."
--Vita Aureliani