Girlfriend & I use different banks. We transfer money between us from
time to time. When she sends me money, when I look at my account
online, in the narrative bit, I get her sort & account details and I get
meaningless text ("000000 INTERN 9270") in what might otherwise be the
reference for the received payment. When I send her money I can add a
reference, but it doesn't get passed across when she sees the payment in
her account, all she gets is my name (and not the reference I added)

Sister & I use same bank, when either of us send money and add a
reference, that reference gets noted beside the payment details in both
accounts (sending and receiving).

Are there any guidelines (APACS?) as to what should happen to any
payment reference. Within the same bank it's not really an issue. The
issue arises when it's between different banks.

I wonder what happens when I pay my (mythical) gas bill for example. I
send a payment to British Gas (for example) and add a reference to the
payment of my British Gas account number (otherwise how will BG tie up
my payment with my BG account compared to their other customers). I am
assuming BG don't have their account with the same bank as me.

Any thoughts?

It's not a problem, it would be useful to have, and I'm mildly curious
as to how the "reference" bit of the payment works, especially between
different banks.

TIA

Allan