It doesn’t work that way. zigbee allows for many different profiles, only two of them work with SmartThings. See the following FAQ (this is a clickable link)
And zigbee 3.0 Doesn’t help as it does not combine all the profiles: only the ones previously based on the “Zigbee pro” profile. Which specifically excludes the zigbee profile used by smart meters. They have a different addressing scheme and are not interoperable.
Is it possible to link a Zigbee device to more than one other system/device at the same time? One might want to still link the IHD as well as a Smartthings hub.
Unfortunately, no. The zigbee profiles that smartthings uses only allow for one coordinator per network.
In the US, it is common for utility companies to make the metering information from smart meters available through cloud access, Which can sometimes be linked to other logging applications with some integration to smartthings that way.
In addition, there is a third-party device, Rainforest Eagle, which can be linked with utility company permission to your smart meter network and then makes the data available through its own cloud. Some people have used that for SmartThings integration, But I don’t know whether that or something similar will be available in the UK.
See the following: