If the answer is CCTV then there must be somebody in one of the overlooking houses who would be prepared to stick a bog standard video camera in their window pointing at the tram shelter and recording on a hard drive. Cheap 'n' easy.
If they stick a webcam in their window then anybody in Dover or the rest of the world can see if some toerag is up to mischief. The one on Snargate Street is an example of one such perusing a similar road junction:
http://www.historexagents.com/shop/cam.php
We have only three webcams in Dover that I am aware of, apart from the visiting cruise ships. Here is the view from the webcam on the Emerald Princess presently berthed on the Admiralty Pier. Usually they are BridgeCams showing the view forward but this one is showing Samphire Hoe and Shakespeare Cliff so is pointing aft, possibly they turn it to point forward when they leave. The big cruise ships, such as this giant, usually have several webcams so that you can select them individually.
http://www.princess.com/bridgecams/ep/emerald_bridgecam.html