that's great! a look at those records will answer some questions-even if there's nothing there.
I didn't know that there was a Boston Spa. I have a book called A Genealogical Atlas of England and Wales-no idea why it's called a genealogical atlas. some bright light took and copied an old, worn map, circa 1850, and put it in book form with a fairly complete index. it's been one of my wiser expenditures in my genealogical research. I use it alot. anyway, it doesn't mention Boston Spa. it does make sense that they should have qualified it. sometimes I run into records where the clerk assumed everyone knew what they meant....hopefully this is not the case.
we don't know much about their life in England. only that Christopher Mason, Jr., was a teacher and had a medical problem-what that was slips my memory at this time, but I think it was something like scholiosis (sp?). we have a missel of Martha Smith's that she gave to her daughter Martha Mason, with dates and places written in brown ink-not of births but of the time Martha Smith recieved the Missel and the time she gave the Missel to her daughter. we also have a family record book-the Victorian period type, where names and data are entered. it's impossible for me to tell what denomination the Missel is, and beyond that, we know nothing of their life in Yorks. the Missel has "Martha Smith Book Morely March 15 1796" then beneath that, "Mart B J M" but under and running up into the M is an S. the J might be a T. I've no idea what the initials stand for. on a different page is "Martha Mason Book Armley Near Leeds 1813". they appear to be written in the same hand. the frontispiece and I suspect the cover page of the book is missing, but the first page extant says "The Psalms of David Immitated in the language of the New Testament and applied in the Christian State and Worship by L. Watts D. D." doesn't seem to give any clue, and it may be a Christian text, without preference to faith.
unfortunately, that's all I have. nothing was left regarding the Moffitts, and only a little regarding the Mason's.
I hope some of this is of help. sometimes another person's perspective helps bring the obvious (or obscure) to light.