No plausible deaths listed in the Hemel Hempstead district (which covered Flamstead parish), but she could easily have died in the neighbouring Luton district, especially if she died in the village of Markyate, which straddled Flamstead and Caddington parish (in Luton district) at that time:
d. Elizabeth BANDY, March Quarter 1855, Luton Registration District, Vol. 3b, page 336
or
d. Elizabeth BANDY, September Quarter 1859, Luton Registration District, Vol. 3b, page 266
Alternatively she may have moved further afield. The original iteration of this page had her dying in Winslow district in Buckinghamshire in 1866, although you would expect to find her in the 1861 census were that the case. It's also a long way from Flamstead / Caddington to Winslow.
