I don't know if that is always the case but when I returned to Heathrow from Germany I went through the E-gates using my German passport and didn't have to talk to anybody.
They still had the queue at the border control split into UK & EU and other.
My parents tend to do the ferry which usually has slightly more personal contact with the border people unfortunately. I do think there's an element of older people fussing about their stress though.
I don't know if that is always the case but when I returned to Heathrow from Germany I went through the E-gates using my German passport and didn't have to talk to anybody.
They still had the queue at the border control split into UK & EU and other.