...just to add, the BDR91 appears to be daisy chained between an FCU and the boiler.
The green/yellow earth wires must remain connected together and can be placed in the Hive backplates earth terminal.
If you need to find a tradesperson to get your job done, please try our local search below,
or if you are doing it yourself you can find suppliers local to you.
Select the supplier or trade you require, enter your location to begin your search.
Please select a service and enter a location to continue...
Are you a trade or supplier? You can create your listing free at DIYnot Local