At heathrow they are pretty good most of the time personally i just queue in the non eu queue with the wife and have been told that if its not first entry that it is sometimes possible to go though the eu channel. Which if i remeber correctly happened last time.
We were in the non eu queue i had asked but the first lady was like no sorry. But later the next lady seeing the non eu taking a while and seeing my Brit eu passport in my hand send us over to the eu channel.
The wife has come and gone to the eu on her own and had no particular problems here on in europe.
I think i said this before but having stood by the desk waiting for my wife at gatwick after a plane from some place in eastern europe had come in some of the peoples stories were just so unbelivable you couldn't make them up. A family who here under refuge status had poped back home for a holidaya student who had come here to study looked about 50 and a few simple questions on the subject from the officer baffled him. But amazily enough they all were allowed in.
So its properly nice to have a happy and polite couple not trying to tell them porkies, in fact i have found some of the officers stop us once all the formalities are done chatting for a while as the job must be a tad boring.