Managed to get the part number from Melbury Motors. In case anybody ever needs them here they are. These are for the heated type Mirror glass only. (in my case 2.2 jtd)
9464243680 drivers side mirror glass
9464243580 passengers side mirror glass
Price £10 something plus vat/delivery. You can get them from Desira as well, same price, but they don't seem to be able to find it without you giving them the part number first.
Lou