never mind the bike Steve, that is one mean looking trolley
As for plugs (remembering apart from providing a spark a plugs main job is to transfer heat from combustion chamber to head and thence to the atmosphere) best to start with a cold plug and work up if they foul, even at today's prices plugs are not too expensive, especially the ones for our old bikes.
Should I admit that I recall plugs stuck at 3 shillings and six pence for what seemed decades