As far as I know, with the initial forms that needed to be in back in May, it is done on a first come first served basis. However, I wouldn't panic, as they are reasonable when it comes to people's preferences, and clearly your preferences are for religious reasons. Whilst they may have come to your form as being one of the last, they will most likely do some juggling around to sort something out, so I wouldn't worry too much!
I'd keep in touch with Housing Services; phone them every so often, get on their back a bit about it, and they'll get it done sooner.
Tim.