Hello, I am a solicitor with 20 years experience. I will try to answer this for you.
Has the landlord given an alternative date often worded like this. "..at least 2 months after this notice was given to you"?
Also did you pay a deposit, and if so is it in a deposit guarantee scheme, and have you been given notification of which scheme it is in? If your deposit has not been protected or you have not been given notification of the protection the S21 notice will be invalid.
Was there more wrong with your kitchen that the oven not working? What does the tenancy agreement say about responsibility for maintaining the oven.
Can you post a copy of the Notice?
I am a little confused as the notice appears to be dated 10.06.16 with the notice period expiring on 17.08.16.
If served before 17th June that would be valid.
The October 2015 rules do not apply to your tenancy.
The clause in the tenancy agreement does indeed seem to mean that they can only serve a notice that gives 2 months notice expiring on or after the rental period. That is said to be the the 24th in the TA.
They seem tot be using an out of date form of AST and have not complied with their own notice provisions. The NOSP is invalid.
No the person you spoke to doesn't understand the rules right. It was the case pre October that a straight forward 2 month notice period was sufficient (although it was wide spread wrong belief that this was not the case). You can get extra time through fighting the notice on the basis of the express clauses of your tenancy agreement. as stated in an earlier answer. Apologies fro the delay in replying.