Hi all, I'm about to do the annual service and I plan to do a coolant change. The specs show my system contains 12 litres which is is a decent amount to try and get out, I think I'm right in that the hvac system does not alter the flow of coolant instead it changes the airflow so if so the coolant ought to drain out from that part? Also there's the rear sub system in the nearside boot area, would that be just a matter of removing the feed and return hoses? As for the engine block I'm really not looking forward to that, being the 24v 2.8 there's not a lot of room. Anybody know if I'll have to pull the thermostat out or can I drain it another way?
Any help would be greatly appreciated.

If it was me I would drain down the rad as normal,possibly pull a hose from rear heater and that's about it. Pulling the stat won't drain anymore from the block as draining from the rad. But what you could do is introduce a problem by causing a leak.

I echo the above. There isn't much need to drain everything out, most of it will do and having worked on a V6 I know the limited space you'll have :)

On a side note, its pretty easy to get airlocks on these so when you refill it the key is to go super slow. Put a small amount in the reservoir and then allow plenty of time for that to drain into the system before repeating.