Thanks again for your input, it is really appreciated.
This issue has already been through the complaints process and to the ombudsman a number of months ago. They made a judgement that E.on should compensate me for the poor service and take the next steps in order to connect the meter to my device. The exact text of the ruling was:
"To fix this issue moving forward, I will ask that EON Next take steps to attempt to update your smart meter system.
If for any reason these steps fail, as EON Next has already reported this issue to the DCC, it would have taken the steps required to connect your meter to your device.
You ask that EON Next repair or replace your meter/IHD however as your meter is communicating with EON Next, this indicates that the meter and communications hub is in working order and not in need of any replacement. The only issue is with the IHD which EON Next are not able to replace as it did not install the metering system."
However, to this date I have had no communication or seen no evidence that E.ON have made any attempt to resolve the issues with the smart meter/HAN and the IHD. I thought this the best place to attempt to get support as the people here generally seem a helpful and knowledgeable bunch. At the time of the complaint I was categorically told by E.ON that they could/would not send an engineer out, however it's disappointing to see that other customers in the same scenario are receiving engineer visits and having their issues resolved. As the company who installed the meter (Symbio) no longer exist, it is impossible for me to go to them for support. Additionally this fault began following the switch from Symbio to E.ON at which point the meter was well under the 12months warranty period. It was E.ONs lack of response to my initial complaint, delay tactics and lack of action that pushed the meter/hub/IHD over the 12 month period.