I don't really know what to suggest but I do know what you mean by the housing team being rude- my mate called up with a query and was given brief, un-helpful information and was hung up on. I wouldn't think your unconditional offer would make any difference: I don't think the university would give you priority over other applicants because of that. I know some universities also allocate accommodation based on how far your current address is from the uni..? Don't know if Portsmouth do that. But really, it's too late to get a place in halls now: I assume that the original places that were rejected have now been given out (hence, why someone I know got James Watson about a week ago, another got Greetham ect.) Private rented is great though- if I didn't want catered I would have gone for it! It can be a lot cheaper- my friend is paying just £66 for hers and it's a nice place! haha.
As a friendly suggestion to the housing department as I know they are on these threads- next year more communication would be greatly appreciated by future freshers. From my own experience, I had no idea why some halls were being released and others weren't: why Rees and Burell were taking longer and how long I was expected to wait. The twitter feed was useful as I could tweet and get a response quickly, however, it could be more useful to have tweets/ emails going out to everyone generally such as: "Within the next 2 weeks guildhall halls will be allocated, if you do not receive an email.. ect." I noticed that the twitter feed was frequently answering the same questions and this would make life easier for both us and the department! Similarly, a lot of people found the next step after receiving a room difficult and from the freshers' Facebook group I know many people were calling up and emailing with the same questions. Emails with step by step explanations could be useful in this instance.
With all that said, I was very happy to receive Rees hall and am so excited to move in in September! xD aha