I gave my tenant 2 months notice to coincide with the end of contract, but I did this via a letter, not with a section 21 form. Is this still valid in case they don’t leave? Now reading about the section 21 form should I now issue this, but with the originally agreed move date (now less than 2 months)?
No. You have to use the prescribed Government form 6A
but now that I haven’t done that, do I need to use the form and give another 2 months notice?
Yes, you do if you want it to be accepted in the court.
If you think the tenant will just leave, then you dont need to do anything. However, if you think theyll make you go to court then yes, of course.