So the trails doing a great job but I'm worried because I've no idea where I can get new tyres for it.
The wheels have Morris hubs and the tyres are marked 5.20-14 and Dunlop Goldseal C41. Quick fit laughed at me

I want to take it camping which'll mean some lomg distance motorway driving and I think I need to either find a spare wheel and somewhere I can get new tyres or find a modern car wheel that will fit so I can swap the wheels, get a spare and find repairs at standard outlets.
Does anyone know where I might get a spare from and / or what modern car might have suitable sized alternative wheels?
Many thanks
Jon