From what I can establish we are NOT in a periodic tenancy.
Due to some difficulties at the beginning of our first 6 months living there, he decided that every 6 months he would sign a new 6 month contract with us, so (he said) if there were any future problems he could get rid of us easier.
So on the 4th of May 2007 we signed a new 6 months fixed period contract, an Assured Shorthold Tenancy for a Furnished home as the other 2 were (its actually unfurnished)
From what I can gather, this means that he should have moved our deposit over to the deposit scheme, im just trying to get some more confirmation from our resident experts, please
Also, if it helps, he raised the rent (a week before the next payment was due, this new rent is reflected in the new contract, while previous contracts would have the old rent amount)