Hi
This might be grabbing at straws, but looking on FreeBMD for districts Huntingdon and St Neots for the time period 1881-1891 there are several deaths:
Lewin, Charlotte, 73, Huntingdon Dec 1884
Lewin, William, 79, Huntingdon Sep 1887
Lewin, Harriet, 20, St. Neots Mar 1889
Lewin, Jonathan, 67, St. Neots Mar 1889
Lewin, Mary Ann, 72, Huntingdon 3b164 Mar 1889
Lewin, Thomas, 67, St. Neots Sep 1891
The only likely ones are William in 1887 and Jonathan in 1889.
So looking in 1881 for Jonathan finds him in Brington with wife and family, but looking in 1891 finds his widow Emma in Tilbrook (4.6 miles away) so Eliza Pryke could not have been housekeeper for him!
Looking in 1881 for William finds him in Ellington with his wife Charlotte, his wife dies in 1884, so he would need a housekeeper for 1884-1887! I appreciate that William is a bit of a long shot because of his age but he still seems to have been working as a mole catcher in 1881. And Ellington is only 6 miles away from Catworth.
Helen