If the modem has a battery back up then that sounds like FTTP and shouldn't be touched.
That was what rang alarm bells with me, but apparently no sign of fibre and photo is FTTC modem. Does seem odd that a FTTC modem should be fitted at a new build though.
So do I need a hub 6 with a red WAN port? like this below?
Yes, if you have FTTP. Can you post a photo of your actual modem.
To completely clarify, if you have an FTTP service with a fibre connected modem you need the modem and a hub with a WAN port. If you have an FTTC service with the modem connected to the normal phone line, the modem can be removed and the hub DSL port connected to your phone line.
I just have a basic BT infinity 1 package, fttp and fttc don't mean much to me I'm afraid?
I'll post a picture later today, currently in work.....
Infinity is just a marketing term, it can be delivered by 2 technologies. FTTP, Fibre to the premises, you will have a fibre optic cable connected to the modem. FTTC, Fibre to the Cabinet, service is delivered to the premises via the normal copper telephone cable. We need to understand if you have a fibre optic cable connected to the modem or whether the modem is just plugged into your phone line. A photo will help.
As suspected, FTTP. You need the replacement hub6 with WAN port as per the graphic you posted.