I seme to recall a while ago some people were after the big red plug on the wiring loom where the solenoid is connected and the main fuse lives and apparently they are/were rocking horse poo. This morning, I spotted this on eBay.

http://www.ebay.co.uk/itm/Starter-Motor ... 43bd340c2f

Can't vouch for the quality of the item, however I have used the seller before without issue.