An MPAN or Meter Point Administration Number is a unique number linked to an Electrical meter and is used as a reference to said same supply, The number is 13 digits long.
MPRN or Meter Point Reference Number and is used for Gas supplies + meters. It is essentially the same as an MPAN, but has a different structure, being only 10 digits long.
We will typically ask for these numbers as it allows us to provide a quote for your supply with only this number, along with your annual usage amounts.