Hi David,
Thanks for that, this Thomas does seem to be a problem!
I found his wife and children in 1881, but no sign of him.
Sarah Ann GILBERT Wife (Head) M 27 Luton Sewer (Straw Hats)
Chas. GILBERT Son 8 Luton
Edward GILBERT Other 8 Luton
William GILBERT Other 5 Luton
Mary Ann GILBERT Daur 2 Luton
RG11/1648 Folio 102 Page 12
13 Adelaide Terrace Luton Beds
He married in 26 JUL 1871 to Sarah Ann Samm at Christ Church, Luton (IGI) so is still single in 1871 census
A direct descendant of his believes he died in 1882, but I'm going to have to contact him for the details. I can see this in freeBMD
Deaths Jun 1882
Gilbert Thomas 37 Wellingbro' 3b 92
but (apart from the age) I have no proof that it is him!
Thanks also Sandy for looking.
Cheers Rob