You hope they don't go in the hive! If they get desperate enough they will (mine were last winter due to long confinement) and that spreads a very infectious bowel disease called Nosema, which can decimate colonies. I treated for it last autumn, and had a probable case this spring anyway.
Your friend is right about the temper of the British bee; the same applies to a pure strain of any European subspecies. It's the hybrids which are nasty. An organisation called BIBBA (Bee Improvement and Bee Breeders' Association) is doing genetic testing of possible native strains. I may get mine done, as I'd like to know whether they're really native, or whether, like some, they're hybrids which look like natives. BIBBA's been almost moribund for a long time and I'm hoping it can get moving again.