Thanks for the help,
I think it's an SX3 (purchased second hand)
IMAG0354.jpg
Just had another look and could probably just run the SX3 (?) diff, as it looks wide enough to make up for the offset, however it's got a different number of teeth on the pulley, and look a slightly different size !
Here is a picture of the two pulley's and you can see the one has a large diameter hole.
IMAG0356.jpg