Hi JimC. You've cured it
I tried the FAT32 formatting which made no difference, I had been using the cameras internal format facility.
I then tried your link and downloaded the SDFormatter, ran it and tried again. I watched the timer approaching 1min 40sec and it continued recording, I stopped it after 12 minutes. Everything now seems to be working perfectly, I can't thank you enough. This was a very impressive experience for me you've completely solved my problem. Thanks.
I shall post some aerial video when I've got some decent footage.
Again thank you so much.