Right, changed the vacuum pump gasket... and....
I'm certain it's the headgasket!!!! No signs of leaking from the vacuum pump. But looked very oily again round the headgasket. Wiped all clean while the vacuum pump was out the way, so no traces of oil around the headgasket at all.
Put the vacuum pump back on with new O ring, then started up and let it get warm - so far so good.
Took it for a good thrashing round the block then had another look. There is definitely the first signs of oil seeping again....
Oily mess before:
After clean-up and then a good thrash - see the start of oil seeping from between head and gasket again...?:
It's still not losing any coolant and coolant doesn't look contaminated. Is this a big issue for a D24T? I told my mate that works in a garage and he didn't seem to think it an issue at all - he says all diesels leak oil not to worry - even though I stressed it was the headgasket.
We're planning to go on hols in it in 2 weeks - will probably cover 1000 miles in a week - so what do I do?? I don't have the time (and probably not the tools for this as I am told it requires some special tools) to fix this before we go....