You've had some good advice. At themoment you seem to be trying to make your LLs life easy, to be doing as you ar etold. That's not how it works and he has no right to do any of what he seems to have done.
That would make me go right back to the beginning of your tenancy and check he has done everything properly
- full inventory
- deposit certificate and required paperwork within 28 days of tenancy start
- Gas safe certificate; smoke and CO alarms
- Electrical certificate, became law last year, has to have been done by now.
- S21 paperwork . When did he give you notice?
On or after 1 June 2021 it has to be 4 months
Between 29 August 2020 and 31 May 202 it should have been 6 months.
So unless he gave you notice back in January or March he has only made a request, which you can refuse until you receive the correct paperwork, - and that will take you up to November, Christams even.
Those viewings, tell him no more. You absolutely have that right. he had 2 choices: do it all propery and help you move out or to act like a twat. He has chosen the latter!
You could baragin with him, tell him that you will be out as quickly as possible if he releases you from the 1 month constraint or you will have to wait until the very last moment as you cannot afford to move at the moment. And all viewing will have to stop.
Most landlords who want to sell understand that they need to have a more relaxed attitude to notice periods and final payments. He is being odd, as someone else said, want to have his cake and eat it.