Oh sorry Alex I think I misunderstood your situation.
If your fixed term ends on 1st March, then you can usually move out on the last day of the tenancy, without giving any notice, as described in the original post here.
If you stay even one day longer, the the contract will become a periodic tenancy and you will have to give notice one month’s to terminate it.
As I understand from what Tessa wrote, clauses demanding the tenant has to give notice if moving out on the last day of the fixed term will be seen as unfair clauses. That’s Tessa’s point in the post.
In this case, the tenancy would end on the last day of the fixed term, they would need to return your deposit within 10 days. Because the tenancy would be terminated and you would have vacated the property, they would not be able to charge you rent after 1st March.
It is always best to communicate your plans with the landlord and not to just spring this upon them! We always recommend mutual agreements wherever possible, as these work best for both parties.
Hope that helps!