Following my last post, I´m wading my way through the Radio Times clippings in the Cuttings Archive (link), and I found something which I´d not seen before, an appearance by the first Doctor, together with a Dalek an Zarbi, in the Captain Pugwash cartoon from the Radio Times (Cover date 27 March to 02 April 1965). This accompanied the screening of episode one of The Crusade.
The frist Who comic strip had appeared in TV Comic in November 1964, so it´s not the first comic appearance of the Doctor, but it maybe the first cross-over appearance, or first ´official´ cartoon appearance if we classify it as such (and seperate from comic strips).
The first ´unofficial´ appearance goes to Boys World magazine, which from May 1964 included a cartoon called ´Doctor What´, a spoof strip in which inventor and William Hartnell impersonator Doctor What gets up to all sorts of trouble.
Does anyone out there has any more first Doctor comic/cartoon information to add to this? I´ll put up more information on Who in comics soon...