No leap of faith required

Lordenshaw Rock 3q
"....is the most interesting of all: a near-horizontal rock lavishly stippled with 'midget' cups, and carrying on its near-horizontal surface a large basin surrounded by a groove, linked cups, and a cup and ring".
Stan Beckensall

Rock cut basins are a global phenomena and make complete sense in many different contexts ranging from domestic use through to ritual contexts.
Just because North British basins are occurring with c&rs it doesn't mean to say that Irish Bullauns are of a similar age. I'm afraid that your gonna have to find an Eel Stone in Ireland before you can start comparing contexts.

As for dating these basins to the Neolithic, your assuming that our c&r's are Neolithic too. That is something that we cannot say with any certainty. C&Rs could possibly have a time span starting in the Mesolithic and finishing who knows where.
I read a paper a couple of weeks ago concerning a carved rock that was 'enhanced' with an extra cup by a man known to the author of the paper.