Thank you so much. I did check if my CC was stored and it's not so I now have peace of mind, thank you.Make sure you don't have a CC stored on MDE (you can find that info under My Profile in MDE). If there is one stored delete it. It will not affect your reservations or ADRs.
Disney will ask you if you would like to place a CC on the room for charging privileges, but you are not required to do so.
Hopefully this helps. I'm not certain if there is a difference with MDE in UK vs US.