Does the tenancy contract say anything about the method of serving notices?
So it started late Jan/early Feb 2012? In which case, the earliest break would be late July/early August (notice served two months earlier).It was a 12 month agreement which was supposed to come to an end end of January. Six months break clause would have been a 2 months' notice in April.
Even if they prove they did give notice in July, the break clause apparently requires two months' notice, so the T would be liable for rent for a further two months.They dodged the question about written notice and said they sent me an email in July which they can not produce either.