How to contact the home office after waiting six months for naturalisation decision?

Hey Guys,

I am getting to the five month mark on my citizenship application. I am starting to prepare that I will not hear anything back and I will need to chase the home office myself on my application.
Could people please tell me the best way to contact the home office in regards to a decision not being made within the 6 month period?

I know you can call up the home office, but you cannot get any information about your application over the phone.

Please let me know.

Thank you