Actually just found a much better and more useful bit of conversion software ‘Wondershare video converter platinum’ This software is perfect for working round and re-converting your HDV3 codec files. you can also open up multiple instances of the program too so you can render multiple files at once. This has saved me a lot of time and a few tears i can say.
Just thought i’d pass on the info for when the same problem happens to someone else
I feel a little happy for beating apple there 😉
Thanks everyone for your help