I just looked at the pipes, and was wrong above.
The thermostat is blanked off, but depending on the type of housing you have, the pipe that runs between the inlet manifilds is still connected up (on both engines). I have a 33 new type housing and have the two smaller bore connectors blanked on it.
The alternator mount block is connected direct to the expansion tank.
The small bore overflow pipe on the expansion tank is blanked off
Thanks for going out into the cold to check!
We had a good stare at the pipes and manual last night and with the info you have all kindly shared above worked out what is going on and what we need to do. I'll detail this below as best as I can in case it helps anybody else.
On ours (with an early 33 set up we think) :
The approx 40mm hoses from both inlet manifolds take hot water from the engine to the thermostat housing.
The hot water feed for the approx 15mm bore heater hose comes from the thermostat and this we need to blank off.
The heater feed hose has a small bore 8mm T to the expansion tank that we need to blank off at the expansion tank.
There is an 30mm bore hose from the thermo accross the engine to the alternator block which is a bypass for when the thermostat is shut. As we still have a thermostat this still needs to be there, without one you would probably blank both ends of this off as well.
Obviously the rad needs to be connected at both ends!
The alternator block part is an 'inlet manifold' for the bock/pump fed from the rad, heater return hose and thermostat bypass hose.
The heater return hose feeding this has a 15mm bore T to the expansion tank with no heater we need to go direct to the expansion tank from this.
The rad also has a small 8mm bore hose to the expansion tank which we need to keep.
By loosing the heater bypass hose fitted at the moment we loose about two feet of hose and about 4 joints which not only makes it all a bit simpler but reduces chance of leaks as well as improving cooling so its a bit of a result all round.
Water wetter and "4Life Advanced Engine Coolant" as suggested by David C also sound like good ideas. (and come under the non capital 'consumables budget' when asked questions about how much that bloody thing in the garage is actually costing...)
Many thanks for all the replies, once its in I'll post some pic's