I confirmed that there was bubble inthe expansion bottle. I have now removed the head. It appears that some has been there before me with the removal.
Upon inspecting the gasket it had blown between NÃ‚Â°:2/3 chamber. but I could not see not coolant tracks anywhere. This blow would explain the slight stumble I was feeling but I can not explain the coolant loss. As said, it looks to me like the head has been off (paint pen crosses on all bolts) but the gasket looks frail tatty.
I'm going to check head is not worped tonight but it looks fine. (FYI, I can still see the daihatsu symbol on the valves!!)
I have been all over the cooling system and can not any leaks. Could this blow I have be my coolant problem?