If it's any help, I have Charlotte's burial, 27th Oct 1847 aged 67, at St Mary Hemel Hempstead, her abode was Frogmoor End. Fits in with John & his new wife Mary in the 51 living in Frogmoor Mill Lane, Two Waters. These places are all in very close proximity & all come under Hemel Hempstead.

There's a marriage on Family Search Pilot for John Tomalin (sic) to Charlotte Ivory, 16th Nov 1805 in Abbotts Langley, could be the right one, Abbotts is also in the same locality.
I see Mary Tomlin is in Luton on the 61 with daughter Lucy & a son William, crikey, William must have been born just after his father died.

If I can help with any thing else I'll certainly try.

Maddie