Feel free to shoot me down in flames here, but perhaps there's some logic to this "block ordering"? If you have sat, or even prefer to sit more towards one goal than another (eg C Block) - and bearing in mind that I would imagine most tickets will go from the middle outwards then you could be...
I've had a season ticket every year at Withdean and am booked in for Friday Jan 14th at 3.30. I think they have 'pre-booked' people according to number of years you've had a season ticket, which is why the dates are a bit random.