the coil doesnt need earthing, but there should be one on the gearbox or the gearbox mount bracket!
Later MK2s & MK3s had an earth to a stud on the rear engine-> gearbox bolt, which is a much better design. Also MK3/late Passat/Transporters etc have much better battery cables, worth looking at upgrading

I pinched a transporter -ve and a MK3 +ve cable, looks like they'll be the right length for my cabby
