Hi Booth, looking over your comments since January it looks like you have been on estimated gas readings and have just received a quarterly bill which covers March to May, it could easily be £600. To avoid shocks like this send in manual gas readings which will generate a bill each time you submit them. Maybe not so important in the summer as fuel use is low, but starting in October try sending in readings every month or so. Eventually I suppose your gas meter will get paired with the rest of the system and will start to send in readings for you. At least I suppose your smart electric meter works, it seems the gas meters do give a lot of problems.
For your information the gas meter is battery powered, and to save the battery it transmits locally to the electric meter every half an hour. The electric meter does the communication to the IHD and to SP. Likewise to save the battery the gas meter screen is usually blank and it has to be woken up by pressing buttons to show a reading.
Did your recent gas bill show a reading close to your actual reading from the meter? if so, you are up to date, but if your actual reading is a lot lower send in the actual value. Good luck.
I'm in the same situation .. stupid gas meter display is blank .. displays a message "Network Inactive (F)"
Pressing other buttons let's me get a meter reading manually.