Ta ratty, but one sunny day doesn't make a summer does it?
Having said that you are quite experienced. Do you know anyone who can look at it for me and/or do the work?
Where are you located? If you edit your profile you can add your location. This may help people in advising you of a decent local garage.
I am allegedly pretty experienced (It's part of my job). Unfortunately it didn't stop me buying a vehicle with a cracked head myself.
It does make me feel better that from day 1 I have been right on all counts with my vehicle. My landy came up clear on 3 seperate occasions with both sniff and compression tests performed by an engineering company. I could drive my landy a thousand miles and have no problems. I could also drive it 20 miles and have it blow a hose or kick its coolant out. I kept telling the engineering company this and they kept saying it was fine. In the end I said enough is enough and got the engine stripped. It turned out that my head was shifting on the nylon dowels and that the headgasket was in fact blown. I had the head skimmed and pressure tested and then put back on. I have driven a further 6000 miles as it is. Every now and then I would have to replace something small. Thermostat here, expansion cap there, temp sender etc. I got fecked off a month back and took it back to the engineering company who did the work. They told me again that all was fine. I disagreed and told em to look harder. They took the head off and told me the headgasket was ok. I told em to check the head then cos it aint right. They checked the head again (this time more thoroughly). It turns out that I have 2 cracks. One in the fuel rail and one in the inlet manifold. Both were missed previously.
Experts can get it wrong as well as amateurs. I'm not saying that in your case it is definately terminal. I am saying though that I took my landy to a place with more expertise and equipment than myself and they got it wrong. Badly wrong, and on 5 seperate occasions.
The number of landy experts that thought I was mad when I told em my headgasket was gone was unreal. People on here too. The verdict by everyone was that if it was gone it wouldn't drive as well as it does. Just shows that not everybody is right all the time.
I really do hope for your sake that everybody is wrong on this thread and that it turns out to be a knackered viscous or a weak expansion cap etc.
Unfortunately I was in denial about my own landy even though in my gut I knew what it was. The problem is that if you keep in denial over it you end up wit a vehicle you wont trust. Because of this it wont get driven and that being the case you might aswell not have it.
Good luck with sorting yours out.