best approach to get let property back

Possession - Section 8 and Section 21

I have a dilemma and don't know the best approach. I have 3 long term tenants, all rents paid to date but I need a house back for me to live in. I have sold my home and the house I wanted to buy has fallen through. I don't want to loose my sale and the best way forward is to take back one of my rental properties. One of them in particular needs quite a lot of work which is impossible to complete with a tenant in there but I could live with the mess. All of my lets are currently on roll over contracts so normally I could just give 2 months notice - I am surprised one of my tenants hasn't taken the suspension of stamp duty has an opportunity to buy but maybe they are in the process!! Now I am utterly confused with the governments current position on obtaining properties back. My husband believes we should just see the tenant of the one property and explain the position to her and see what her response is. I am more inclined to contact all three tenants and see what their plans are just in case one of them is about to purchase. In any event am I allowed just to serve a tenant with the statutory 2 months notice from a rent day even though I know at this time they can refuse to leave for 6 months . Is this going to end on 31st May and I can then give 2 months notice. All my tenants are very good but I know their dilemma will be the great shortage of available lets in our area. Also because all my tenants have been there over 5 years I have not tended to increase rents to the current market levels because they are doing the decorating and general upkeep.