Hi Bret
If you go onto Chambers website, you should be able to confirm which mark it is or post the serial number on here and some-one will know
The parts you want should be available from Chambers and if not, from John Knibbs at Shustoke near Coalshill. You can get his contact details from his website. The parts you are after may well be common to the Mk 4,5 and 6 but Chambers parts diagrams should confirm
ATB
John