We have an awful musty smell from behind out freezer, any assistance/advice please

Move the freezer out and check under and behind it. Also check around the compresser area of the freezer

I will ask a neighbour to do as you advise (I am 80 living alone) and will let you know the results.
Thank you for your assistance.

First thing comes to mind ( sorry) would be a dead mouse or something under it. Good luck, we all should move Fridge, and items out and clean good around them, but I know it is harder as we get older.

Thank you so much, my neighbour had to uplift one of the floor boards under the freezer and guess what he found? The remains of several mice, he sprayed the cleared area with Domestos Bleach.

Well done Fr Chuck.