Correct, when my Robison’s local started selling Tennants Extra Lager they had to pay a surcharge if the Einhorne sales didn’t match the Tennants. So any unsuspecting customer who ordered a pint of lager instead of naming one of the two brands were always served with Einhorne.That was Robinsons, it’s German for Unicorn, like the one off their logo. Hyde’s did the same with Amboss (anvil).
I never cared for Lees’ beer or their pubs back in the day, so don’t ever recall what their lager was called.