UPDATE:
So. Got the b bolt out. Inspected it. Threads not damaged but small pieces of swarf between the threads...presumably from where I'd cross threaded it

Decided ''oh well, ive fekked it now anyway'' so removed the lifting eye. This had a shit load of swarf around the bolt hole, also presumably from the head.
So, refitted b bolt. wouldn't go in and it was just spinning. so I tried something.... instead of fitting bolt, tightening and letting the dipstick/transfer pipe bracket be drawn up....I pushed on the dipstick tube so it and the t-pipe were flush with the head and then wound the bolt in.
it did get quite tight and I was thinking any moment that it was going to ''go limp'' and start getting looser (id fekked the threads anyway remember)..... but it wound right up to secure the pipe. ran the car, got it up to temp. felt the top hose and it got hot. and no leaks and no cambelt squeal.
took it for a drive and got back.... no leaks.
I count myself very very lucky. this was 100% luck compared to judgement in my opinion.
will of course keep my eye on it too.
am well aware that if it ever has to come out again I might not be so lucky.
thanks for all the help boys. really appreciated.
