mk3 Gearbox & Diff oil change advice

Hi,Just a few questions.

1) Are the instructions re oil change for 6 speed Gearbox and Diff relevant to the Mk3.5 as well as the Mk3?

2) Is there a problem identifying the drain plug on the 6 speed Gearbox ? I believe I remember a caution in the dim and distant past that there is an identical plug near the drain plug which can drop a lay shaft in the gearbox if it’s removed by mistake?

3) I understand there is oil required in something called the Turret?? which may also needs changing?

I’m asking because I need to do mine before June of this year and I’m pretty clueless about it.

Cheers
Gales