Transport Jock,
If it helps I got an email back from the Movenpick 4 days ago offering me a rate of 450dhs per night, they said it was for a "superior room" so don't know of that is the same as FD book, but they said it was an FD staff rate, but it comes out so close to the full allowance that it seems easier just to let FD sort it out.
The other problem I can see is that the hotels all want credit card details if you book, and if for any reason FD change the start dates you could possibly be left with a room paid for that you don't need.