'Deed of Surrender'

Rent Arrears

I have tenant who, to put it mildly, has not been a great tenant. I have had numerous periods of no rent being paid and some anti-social behaviour which although not extreme, has given grief to some of the other tenants in the property. I took him to court and was granted an 'Order for Possession' over a year ago but before I could go through with it Covid but the brakes on everything. I had also been granted permission to take the matter to the High Court, as I felt at the time this would be more expidite.
Last month part of the rent (he is on housing benefit) came in but a significant proportion did not - for some reason there are two payments. His excuse was that his daughter had withdrawn money from his bank account and therefore there was not enough money in it to cover this payment.
I had decided that if there were any more problems then I would go through with eviction via the High Court. I gave him a letter telling him that I wanted him to leave the property within two weeks of his own accord otherwise I will be continuing with the High Court process to get him evicted. If he leaves I have offered to help him move and a little 'sweetner' in an envelope once he is out. I told him that he would need to sign a 'Deed of Surrender' on the point of him moving, moving all his possessions out of the flat. Surprisingly he has agreed to do this and is in fact quite positive about it.
I just want to know if the 'Deed of Surrender' is sufficient and that he has no recourse legally after signing this in front of a witness who also signs the document as well as me. Have any other Landlords used this document successfully ? I did not know anything about them until last week and I don't recall seeing them mentioned before.
If he does move out voluntarily this will save me time and also cost me less as the sweetner I offered him is less than the amount it would cost me to go through the High Court process - and of course be a lot quicker, enabling me to get on refurbing the flat and get new tenants in.
Opinions and expericence feedback would be much appreciated.......