Didn’t have access to vacuum fill, so went old school - let the hot engine cool slowly and draw the coolant in - worked a treat. The process in the manual was useless !
Coolant hoses were disconnected as heads etc were removed, water pump and...
Just to update… found a faulty coil pack, replaced and engine now running nicely, without any misfire :)….
But now overheating and cannot seem to properly bleed the system as some hoses are cold, some empty, despite filling the tank and running...