...had a bit of rock back on forward using the straight edge. Now when recrowing I see can see a groove in the fret which I think Is caused by lowering the fret too much.
Can you elaborate please? I'm having trouble completely understanding the issue (the "rock back on forward" is what's confusing me).

If it's just one fret that's too low, you buy some suitable fret wire and just replace it. Then level the one new fret to match the adjacent ones.
Another option, which is way extreme IMO, is re-level all the frets to accommodate the low one. This would be a last resort though. There may be other options but I need to understand the problem better.