Jamiec360

They are standard tungsten carbide PCB drill bits, they will snap unfortunately at these sizes it's in their nature. Easy to get from Amazon for between £5 and £15 depending on how many of each you want. The last box I bought was 5 of each size for about £12 on prime.

Bought some from Dorking Models about 3 weeks ago. They do mail order too if you're too far away. Had the Uschi stuff too. They're only open Thursdays to Saturday's