Maybe if you had paid for a TV licence in the first place - like the law says you should - you wouldn't have this problem.
Shame on you.
Well considering that a student's term time address is legally only a correspondence address and isn't recognised in law as their place of residence, it's a bit much to make students have a TV licence at all if their home address has one.
But what happens if they simply remain at the door and refuse to leave
Well if they did, what are they going to do? Kick the door in? Hardly
In any case, they won't hang around outside because they have no motivation to. TV licencing people might be dressed up in a police-esque uniform, they might be referred to as 'officers' in the propaganda that comes out of them, but they are actually nothing of the sort. Wheras a policeman would hang around all day because he has a duty to see law and order upheld, a TV licencing guy is just someone being paid to do a job, usually as a sideline.
If you won't let him in, he's not going to waste time standing around outside your house when he could be knocking on his next victim's door, and picking up his comission for succesfully catching someone.
Or are TV licensing detector vans an urban myth?
They're not an urban myth per se, in that there are real detection vans around. What is true however is that not every detector van is real; many are simply empty box vans driven around areas where a large number of people are suspected to be watching TV without a licence. As well as that, even the real ones are not as accurate as they'd have you believe; if you live in a densely populated area, they won't be able to 100% confirm that an tie an unlicenced TV in use in your house is actually in your house.
They do have handheld detectors for use in blocks of flats etc, but most plesant flats have an intercom system and so would need to be buzzed in and so they still couldn't get anywhere near your front door. Only if you live in balcony-access flats with no outside door would they be able to get to your actual home. And with the greatest of respect to anyone on here who might live in such a complex, such flats tend not to be located in particularly pleasant places and as such the guy would have to be a particularly brave TV licencing officer to walk around such a building in uniform with a handheld detector.
And above all, remember that no matter what they are able to establish with a detection device, that they still cannot touch you unless they have actually seen installed TV receiving equipment in your home.
What kind of gear do the real detector vans have inside?
The original detector vans had ultra-sensitive microphones which, coupled with the fact that double glazing was not generally available at that time, meant that they could use the vans' equipment to simply hear a TV set in use. AFAIK, such equipment is still fitted to modern vans, albeit supplanted with more advanced kit.
Their main tool now is to use a technique called 'van eck phreaking'. Quite how this works I don't know, but I know that with it they are able to actually see what is being displayed on your TV.
AFAIK however, they can only do this with CRT based devices with poor magnetic shielding, i.e. a standard TV set. If you have a TV set using a flat panel technology, or are using a modern well shielded CRT computer monitor in conjunction with some sort of external tuner (such as a TV card in your PC), then I don't think they are able to do this.