Landlord has sent a fixed term agreement randomly

I'll explain the situation as best I can to avoid confusion

So I've been renting an apartment since september 2012.

In 2016 a new property management co. took over the management of the apartments and in september 2016 I signed a fixed term agreement with them for 1 year.

The fixed term contract I received then states that on expiration of the contract, the tenancy can continue by:

1. Further fixed term by mutual agreement
2. By myself serving notice to claim part 4
3. In absence of agreement tenancy will continue as part 4

In august 2017 I let their agent who I deal with know by email that I'd like to continue the tenancy past the agreement under part 4. They acknowledged this email and said they'd send out a new contract in september (nothing about fixed term). They did not do this and I presumed they were happy to leave it with no contract.

So today after 6 months without that I randomly received a fixed term contract for 6 months starting 1 March with a post-it asking to read sign and send back.

I don't mind the tenancy conditions as they're standard stuff but I am concerned agreeing to another fixed term may affect my part 4 security as I would like to stay here for the forseeable future.

Can anyone advise my best approach to this?