Hi lastlid
We (wife and two kids) all came to the UK via Birmingham airport. I accompanied my wife through the non EU citizen passport line. The immigration people were fine with me doing that. Indeed it probably made their life easier to have us all together in front of them. I advise you to do the same as they will obviously realise that the reason that you are with your wife is to do everything that you can to make her passage into the UK go smoothly.