Thanks so much for all that wonderful info, Scrabble. It's confirmed just about all the IGI submitted stuff and given me a few siblings as well, so that's a relief!
The IGI (proper transcription) has Josephus Inglish s/o Georgei baptised in Emley on 9 Feb 1707 - is that one not there - perhaps under 'I' instead of 'E' (don't you just love these parish clerks and their spelling variations!?).
I see what you mean about Beatrice Mountain, wife of Major, being buried in 1766 - he must have remarried between 1766 and 1768, so it looks as though I've still got a search on for the mother of Mary Mountain, d/o Major, who was baptised in 1772!

John, I've only got one Mirfield baptism booklet - 1796-1812, too early for your Firth children and too late for James Firth's baptism, but there are about a dozen Firth baptisms at that time - so, perhaps looking good?
Thanks again, Scrabble. That's been a great help.
Jill