How many more? 7? "Marco Polo"? 40? 96? 97? 97.....ummm, that is all that is missing right now. You are telling me that every single Doctor Who episode now exists? Ridiculous? Right? Well, no, not really.
Now Philip Morris went out in search for these episodes a few years back and was gone for quite some time. His search yielded 11 Doctor Who and a few odds and ends and that is it. Worth it? Sure, for us, perhaps not for him but wait a minute. What is this I hear about 70,000 film cans being returned to England? Could that be true? Sure. I have stuff in my basement from the time I moved into my house. This stuff is in a box just forgotten about. I haven't had the need to throw it out or even to look for it. Is it possible that archives from around the world have film cans? Who throws away film cans? Can you see an archive just keeping them and sort of forgetting about them? Sure.
I just think that the chances of finding 11 could be the same as finding 90+. If conditions exist in several archives to find material, then why not?
I guess it still doesn't explain that episode 7 but is it possible that not everything was tracked and recorded properly? Did someone video record it? It is possible.
As time goes on, the chances grow slimmer and slimmer. I truly believe that if Morris reports that his search is over this year then one of three possibilities have happened. 1 - years of searching yielded skimpy results and he has given up. 2 - He has run out of money and cannot continue. 3 - He has searched everywhere and is done. If he has indeed searched everywhere (within reason) then chances are that more Doctor Who are found in the future is remote. Sure an odd one here or there might still pop up but I think this is the last hurrah in finding a lot of them.
It would be a dream come true to find all. I think most fans would be happy with what we have or perhaps a few more but 97 would be perfect.
I do believe more is out there and believe it is a huge amount. 97? I don't know about that but I would not rule it out at all.