I'll stick with my original head gasket thoughts, not convinced that condensation is the problem, now the car is running daily. Condensation can be a problem if not enough use, but regular running should have solved that. If you do change the gasket, ensure you go to your local precision engineers for a crack test & resurfacing of the head.
Anyway, if your going to do it yourself, might as well do it anyway...at least you know it's been done as part of the renovations. It's perfectly possible, not overly difficult and will certainly give you piece of mind.
If you intend to pay someone else to do it.....You may need to think on a bit.
TBH there is no point in having a nice gleamy shiny car that has neglected mechanics.