Just as a note, when we're saying that visa and BRP holders can go through the EU line with their UK/EU spouse, it's going to the manned EU desk, same as if you were travelling with EU children under 12.
My IO at Heathrow yesterday was so lovely, she actually (jokingly) told us off for going in the All Other Passports line rather than the EU line. It was a tactical move; there were a lot of families on that flight from Geneva.