Well, I am back home, having spent yesterday afternoon and over night in hospital. I had my stent put in and all is well with the world!
It turned out it was the main coronary artery that needed the stent. The much smaller artery is completely blocked but as the consultant put it, the bit of heart affected by this small artery is getting its supply "through the backdoor".Apparentrly capillaries have grown around the blockage and supplies of oxygen are getting through. The body's abilities to repair itself is pretty amazing.
The stent is nearly1 1/2" long and 3.5mm to 4.5mm in diameter, much bigger than I thought. So now a week's rest to enjoy. I am not good at resting, I get bored easily, particularly when there is a boat to build! But I'll be a good lad and do what I am told... Maybe along with a bit of light leather work, reading and Sudoku to fill the gaps!
The expensive bit of metal in the title is the stent. I believe it's titanium coated with some drugs to prevent stuff from growing on it! The stent itself may not be the most expensive part mind you, but all the other costs of the medical care that made it possible for that stent to be where it is now. Something to be grateful for.