However, I can understand the effect all this must have had. It seems to me that whatever you do, the missus will have to be on board. I suspect the profit and loss situation won't be much different whether you keep+mend it or just sell it. I do wonder if - after 7 years of largely happy ownership - you both might enjoy a change. Someone else may be delighted to get a sound Bongo on the cheap and fix the head.
If the missus changes her mood when you propose selling it then you could revert to plan A (keep & mend). But be sure to fit a low coolant alarm to (hopefully) prevent the next incident. Also, make sure the work is done properly and using pukka parts (How far is Ian Taylor at Market Drayton from you as he is good?).
Tricky choice - good luck and keep us posted
