I'd want to take the head bolts off even less than the system join bolts
The welder came out with his cutting torch but couldn't get the necessary access even on well elevated axle stands to work successfully. He was too concerned about causing damage elsewhere and potentially to himself. He's a well regarded guy locally so nothing to argue with really.
So if I want the engine out I'll have to cut through with the angle grinder. The plan was to cut through the manifolds of the dead engine and the system of the donor car. Then with the parts on the bench he can come back and work more easily to clean out the bolts and I can reassemble a complete system.
But I started to realise this was becoming ridiculous. Something very wrong about cutting through a decent 2.2 exhaust as these are quite sought after and not cheap. Also the concept of removing the engine from a lightly damaged although otherwise very nice 2.2 to a somewhat more needy none Cat'd car just started to make less sense.
The non Cat'd car (silver 2.2) needing the engine will be worth about £2,250 sorted. The Cat'd car (blue 2.2) probably more like £1,500 maybe £1,750 if it comes up really nice. So I'd based previous plans purely on finances.
So the silver car is being bumped down the priorities list and may even get broken. The blue car needs a complete subframe/steering/suspension set-up but that shouldn't be rocket science.