We have looked at buying power supplies etc direct from original industrial manufacturers of the power supply, instead of the medical equipment supplier in the past. Bit of a hornets nest to say the least. When compared to UK / NHS legislation, you need to ensure even if you have the manufacturers code that the medical equipment supplier hasnt tweeked it after they have put it in the medical kit to do something slightly different than the origional spec. Also some original industry manufacturers of this type of kit have a license to the medical equipment manufacturer which means they wont sell direct to you. And delivery can be quite a time, as you are only buying one. So you need to not mention its for a particular machine. In the end we decided wasnt worth all the hassle to save a few pounds.
Benning Electronics where very helpful though.