Problems with Hash Sum Mismatch

Running about ten debian PCs that are updated from a local mirror that runs apt-mirror weekly. I am located in a wilderness area of southern Africa that has very poor long range wifi. I initially mirrored the repos by taking a PC into a town that had adsl connectivity and syncing it there.

The issue I am having is that from time to time when installing a new package or update from my local repo, I receive the Hash Sum Mismatch error. Investigating, I find that the file I have in my local repo was truncated. I delete this local copy and rerun apt-mirror correcting the problem.

What I am looking for is a program that will essentially do the same thing that the apt install does in checking the checksums but not just for the currently selected files for install but for the entire repo. In other words, I want to identify bad files in the repo in advance. I would run this weekly just after apt-mirror.

I have searched for something like this but without success. Surely this has come up before?

Thanks,

Perazim