You don't even need to do that.
Take the data, turn it into CSV.
Remove the surplus information, then compare it with the december one. only include information where post codes are in both sheets.
Due yes/no.. keep the data basic.
Also, for the purposes of checking, it really only needs a few people on the forum to have it - and who log in every day, and check for people that come-a-knocking on the forum door.
There's ''leaked and posted on the internet'' and there's just ''leaked'' -- either is fine.