It was completely my fault.
I had been building brackets for wheel spats all day and had the wheels on and off and then on again and then off again, plus a few other minor jobs on the aircaft and it was getting late in the day, I was over it and all I wanted to do was go for a fly so I put everything back together to start the preflight, including sliding the bush over the axle extension BUT then couldnt find the blot that held it on.....sooooo I looked around for it and kept looking, then something distracted me for a bit then I went back to looking for the bolt, then someone turned up, so after chatting - I said I must get back to my preflight so I started again and checked every little thing before pulling her out and starting up..........or so I thought.
Take off down the hill into the sunset and pull on the brakes to stop the wheels shaking, look right to check the wheel has stopped, yep, look left to see the ....OH SH*&^ the left wheel is perched on the very tip of the axel extension like its about to fall on some farmers head. Had a chuckle at rocky stretching his legs out into the sllipstream trying to get the thing to slide back on. Tried flying knife edge so the thing would slide down the axel.....nothing worked so I just took her home landed on one wheel and when we were at walking pace I lowered the leg and she slid around almost a 180.......... found the wheel and pushed it home.
I always used to think that I did the most overly thorough pre flights and I feel embarrassed about this, but more so I am dissappointed in myself for letting it happen, as it is not the type of pilot I wanna be. I guess you could say its good that it has happened to me because I dont plan on letting anything like this happen EVER again.