James,
I would suggest if that is the case then they are probably running different dates for different schools and will only be showing you available dates for whichever 'batch' you applied through. Given Dave and Hamsterminator both appear to be CTC they have been offered the 11-15 Mar so I would guess this is the CTC window for applicants to go to Waterside?
Of course it may be too early to predict this trend
SJ