I manged to spend a little more time on the CNC mill today, mainly to experiment with a few things.
Thanks to Paul and Alan who replied with regards to my previous post offering advice so I had another go...
When I was watching the cutter profiling the gear I noticed that for the first few passes the cutter was slightly deflecting but as the program carried on and the cutter traversed deeper into the material the deflection reduced.
The thing is though, I think I now have a pair of useable gears so I might try them out in an engine...
P.S. Boring post I know but things will liven up soon...!