floody,
I think if you check with Customs on this but I have done quite a few trips o/s and in all the info that I have read it states that if you are out of the country for longer than a certain period of time, (used to be twelve months) no duty was payable if you could prove ownership of the goods for that period. However as I said, check with Customs I'm sure that they will give you the correct information.
Cheers