Autopool just called, it's running again
Managed to do it without taking head off. I'll get the run-down in the morning as they've got to put it back together yet, and they want to check the other plugs too.
Gutted in one way, as I was gonna get them to do the water pump & ancillary belt while they were off with the cambelt, check it all over while it's off. Never mind, I'll have to use that money for something else I suppose...
But seriously, I'll try and get some info off them for how they did it and I'll see how she drives - big test coming this weekend if she can tow my van for me. He did say he couldn't guarantee it was 100% as they did it in situ, but it all tightened up fine and runs ok.