My wife has an older 14" Inbred with 80mm forks on at the moment which need replacing soon so I need to work out what it will take, just 80 or would it be ok with 100.

It has cable guides on the top of the top tube if that helps identify it.

Should be fine at 100mm 🙂

I had one and it was fine with 100mm forks (they were designed with 80mm forks behind).

The first generation had two cable stops, the 2nd gen had three, and have a thicker toptube so are stronger.

100mm should be fine what-ever though.

This one has 3 sets of cable guide things on the top tube, so sounds like 100mm would be cool