UK Property Law
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If you are occupying the property under an assured shorthold tenancy and you wish to vacate when the fixed term expires then you are not required to give any notice whatsoever. This is regardless of what is stated in the tenancy agreement.
You do not need to give any notice, other than on the final day of the term by taking your belongings and handing the keys back to the agent.
Either they know the above and they are being cheeky, or they don't and they are negligent.
If you stay beyond the the fixed term then it will become an statutory periodic tenancy (from month to month) and you will be required to given one month snotice expirin gon a rent day.
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