I'm sure they can align. But if you don't have your own ground and you need to book stalks, it is much tougher as booking stalks tends to be several months in advance.
Nice one on getting it done for the candidate, though!
Scrummy
Again, I'd suggest ask around. Not every AW is running a full-on commercial deer stalking business, and may find it easy enough to slot in a witnessed stalk within a couple of weeks.
The Candidate who approached me had tried three or four other AW's beforehand, and faced some of the challenges you mention, but working through the list came up with a result that happily worked for all.