As you all know, the non-EU queue for immigration at Heathrow is absolutely insane. I went to Heathrow when I first entered on my student visa and I waited in a queue for about two and a half hours. Now, my visa has been stamped and approved. I was asked various questions about where I was staying in the UK, and my answers sufficed.
Next time I enter into the UK, am I allowed to avoid the non-EU line and go to the British national line? If my visa has already been stamped by an immigration officer (it has a 3 on the stamp, I'm assuming for three years entry, which is the length of my visa), would it be a problem?