The smaller ones are the same as the pins in the rest of the loom connectors, and were quite easy to find at one point. I haven't tried for a few years as I bought a few spares. I don't think I found a source for the larger ones.
Are yours unusable? They can be cleaned up with various methods.
ETA : I think these will do for the small ones, maybe check the dimensions before buying loads:
https://www.vehiclewiringproducts.co.uk ... connectors