When I was in a school, I always used Digital ID, https://www.digitalid.co.uk/ for our ID card supplies.
Great advice, fast, and well-priced. I used an Evolis Primacy, and the system was set up to read the card number of the card which was printed, and feed it back in to AD and various other systems for full integration (ask me more if you're interested on what I had set up). The caddy could handle a good stack of cards, so could be left churning away on the new intakes.