Thanks for all the replies.
@jim1 and JenB:
Sorry I didn't make it clearer in the original post - Thomas and Ann did stay in Saxilby after their marriage. Their children were all born there, and my family has been in Lincolnshire ever since.
@toastbutler:
Thomas was born in 1745, Tuxford. He married Ann in April 1778, Saxilby. Their first child (Thomas Jr) was baptised at Saxilby in March 1779, followed by John (1780), Ann (1783), James (1785) and Elizabeth (1788) that I know of.
Thomas also had a brother I believe - Francis - who was baptised in Marnham in August 1759 and also went to Saxilby in May 1788 to marry Elizabeth South. Their first child (also Thomas) was baptised at Saxilby in March 1789, but their other children were born in Marnham.
@KGarrad:
I don't know what his occupation was, actually. I don't think any of the records I have seen to date have mentioned it. I wonder how I might be able to find out?
Edit: actually, I've just remembered that the record of Thomas' burial (May 1817) on FreeReg lists him as having been a Farmer.
@Sallyyorks:
There was no mention in the register of either of them being "of..." at the time of their marriage, which is one of the reasons why I've assumed that they lived there, rather than just popping over the Trent to get married.
@stonechat:
I'm not sure I've got time to read "Tess of the D'urbevilles" when I've got all this family history research to do