I thought long and hard before posting this!
Opening myself up to ridicule
But I've just spent hours trying to get my front wheel back on and thought I'd share so no one else has to
Most important tip is use a front paddock stand that lifts on the stearing head, you will avoid all the problems I had if you do.
Problem 1. The pins on the stand were too long and encroachd the space the wheel shoud have been in, meaning the wheel twisted out of line and the axle wouldn't go in. Once the wheel is out this is very difficult to correct
Problem 2. Although my paddock stand is adjustable, I'd obviously gone to far meaning one side was lower than the other, the axle was trying to go in at an angle and just wouldn't work. It was hard to tell this was wrong when the wheel was in. Again very difficult to correct when the wheel is out, I had to put a car jack under the one side to lift it up
The good news is its all ok now, but hopefully some one will find my mistakes useful by avoiding them!