Hi Mark,
Sorry, yes, William is indexed by Ancestry as 'Collester' - I normally make a note where there's a difference like that. I also notice that I'd typed the schedule number as 39 (same as the page number) whereas it is actually 203, and the full address is 51 Fairclough Lane. I don't seem to have made a very good job of copying the numbers - in the 1851 census I've put p.11 when it should have been pages 22 & 23! It was also German district 2a. It doesn't seem to be possible to search on Ancestry with the piece and folio number any more, which was always useful if you suspected a mistranscription, especially for the IOM where you could make use of Brian Lawson's census index.

I haven't made a serious study of William and his descendants, being more focussed on his brother John so far, and what I have for Wiliam relies on circumstantial matches between the IGI and census, which ought to be checked against the register entries. The suggested marriage & death of Jane Bridson fits well, as does the Braddan baptism of a son John to William & Jane in December 1845, with the 1851 census. If it is the wrong William then we should be able to find another William & son John in the censuses etc to account for them. It is quite possible, even probable, that I have made the wrong leap to John & Sarah in 1881 & 1891 in matching only Braddan birthplace and 1845/6 birth year.

The proposed 2nd marriage to Margaret Hampton also came from the IGI, but that was only a member submission so should definitely be checked with the register before paying it too much attention. This marriage is too late anyway for John to be the legitimate child of Margaret. Of course, in the census, all the relationships noted are with reference only to the head of the household, not the wife, so John could be son of William but not necessarily of Margaret.