You can find your NMI and MIRN on the first page of your bill, just below your customer number. 

If you don’t have a bill handy contact us and we’ll help. You’ll need to tell us your meter number, which can be found on the front of the meter.

Each electricity or gas connection point is assigned a unique identification number. For electricity, this is known as a National Meter Identifier (NMI). A Meter Installation Registration Number (MIRN) is used to identify a gas connection point.