At £6000 for a 38 week contract, you're paying £157/week, which if I remember is cheaper than your most basic contract, and in this year is the approximate price of either ensuite self-catered or standard catered- either way, getting more for your money than through your company. Whilst the longer contract may be better for postgraduates, undergraduates often do not need the full year- flexibility in the length would make the private hall more accessible and affordable, considering it is currently both more expensive per week, and for a longer period of time.
In addition, our fees include free/reduced entry to an annual ball, and a variety of events throughout the year. The one thing that this town is short of is affordable accommodation- considering many students only receive a student loan of £4750 (through SLC) I don't know how you can justify rooms that may be big, but are frankly difficult for many to afford. Actually, that's probably why there are so many rooms left this late in the year, even with the intensive campaign of your PR team. Sorry.
Personally, I only managed to afford standard catered last year by finding a job straight away, and working full time over the summer beforehand. My friends are considering commuting from as far as dundee just to find somewhere that's less than £400/month, as there are very few rooms at that level around town. Please do some more research and consider adjusting some of your rooms to make them more affordable for your average student!