You have to be so careful when drafting possession claims not to give any opportunity for the opposition to raise a defence.
I issued proceedings recently for a client using the accelerated procedure. The notice had been personally served by the clients managing agent by leaving it at the property, so I put in the claim form that it had been served by inserting it through the letter box of the property (as they often are). However the tenant then went and put in a defence saying that the property did not have a letter box so the notice could not have been served! So annoying, I will never mention letter boxes in my claim forms again! Of course it had been served, and he knew it. However as the defence had been raised, the Judge felt he could not make the order on the paperwork (as is normally done in this type of claim) and ordered a hearing.
However the tenant did not get away with it. Not only did I have my lady who had served the notice at the hearing to give evidence to the Judge, but I also served a schedule of costs. As a result of which, when the inevitable possession order was made, he was also ordered to pay over £500 legal costs. I doubt whether we will ever see it mind, but it made the point that if you raise silly defences which result in more work and inconveneince all round (ie an unnecessary court hearing) you will be expected to pay for it.