Purchased a used switch off ebay. I did purchase one earlier this year but it got lost in the post (the ebay seller immediately offered a full refund though), then I put it off during the spring/summer as I was planning on trading in my Jazz but I never found anything suitable. Switches for models with folding mirrors are harder to find to so you have to keep an eye out on ebay.
The mirrors now working perfectly, even the driver's mirror now folds in more smoothly and no longer judders.
It was simply a quick swap job - remove side panel, push the mirror switch out from behind, remove plug and connect the switch.