I guess I would want a few more details.
Are you meaning to make one off additional cards based on requests (like if I was sad that the game does not have Item X from my favorite episode, but you would now be able to make it)?
Or do you mean to be replacing existing cards with different graphics/text?
I am always up for new Dr Who content in this game. It is a rich story/world to draw from.
I mean either. I can take existing cards and replace the art/text, or make up entirely new cards if you want to playtest something that you feel would make the game more enjoyable for you.