I just looked on the JQ website and found the part number for the conversion kit - JQS0033
So I googled that and this turned up
http://www.hobbyarea.com/catalog/pro...3b7a91226148a6
It's from Italy so don't know what the postage would be but might be worth a try depending on how badly you want it ?
Is there no UK stockist to check with any more ? Post into the JQ section in here, I'm sure one of their drivers could help out with a better answer than I can ?