Chris SIf your front drive flange is leaking oil volkswagen do a repair kit
part nr 020 498 085E.
The rear (propshaft) flange seal is nr 020 301 189N
both numbers are for a syncro until g/box nr 4Z05017.
From 4Z06017 and for all other types ARM,ATZ,AXR and G60 types ASU,AWP,AYO,CBB its part nr 020 498 085G.
The rear (propshaft) flange seal for these is nr 084 409 189B.
The front flange kit includes a new oil seal, circlip and end seal, but not the drive flange, they are a very cheap repair at less than 25 euros per side, thats a lot cheaper than a new g/box (or more usually a new transfer box)
The rear seal is not part of any kit and the p/n is for the rear seal only.
for the rod change box the g/box nr is on the underside of the bellhousing and can be read with the unit mounted in the car, but a G60 big front bumper does make this a bit more difficult,
the cable change gearbox nr is on the top of the bellhousing & can be read from inside the bonnet.
also see here for what the g/box nrs mean.
http://www.vwsyncro.co.uk/data/forums/topic.asp?TOPIC_ID=762