WANTED: Leftover bag of Postcrete (or similar) (Horsell GU21)

Leftover bag of Postcrete (or similar)
WANTED
Leftover bag of Postcrete (or similar)
Horsell GU21
DESCRIPTION
#121385686
I only need to secure one fence post so, to avoid buying a whole 20kg bag of Postcrete, I was wondering whether anyone might have a leftover bag (preferably not too old)?