Bandwidth issues Nighthawk M5 router - can these be issues with O2

[TonyHrx]

I have a Nighthawk M5 router. 

I have an excellent 5G signal and it's connected to an external antenna. The router connects to the 5G network fine.

However I have really low bandwidth. Compared to my iPhone, same network, same place, the Nighthawk delivers max 20mb/s - the phone 60mb/s.

Is this an issue with the O2 service, or should I be looking at my Nighthawk settings?

[Oxonian]

Glad to hear that you seem to have resolved your problem @TonyHrx. 👍