We have made a pager that is suitable for fork lifts... I know this post is old and you might not even need these now, but we did sell many of these here in the UK.

There is a new design of alpha text pager in the works and the one shown in this link is the older version. But the new designs might be worth a look. Here's the link to the exact page: https://lrspagers.co.uk/pager-systems/fork-lift-pagers.html and filling in the form on that website will always come directly to us.

I did expect to see more posts for this inevitable ongoing problem but there you go.

Have you looked at the KeyTroller product line? They have a lot of access and monitoring products. They may have something that can help you out.

P.S.
Is your last name really Fart?