Practical advice time, folks: how do I find interesting films showing in London cinemas?
I’m particularly interested in older and moderately obscure films — the kind that will turn up over the course of a year, but that I’ll miss unless I inhale a listings magazine every week.
  Does there exist a website that can take a wish-list of films, and email me whenever one of them is on in London? That seems like such an obvious and potentially-profitable concept that somebody
  
   must
  
  already have built it, but I can’t find it.
Relatedly, does anybody want to come see some films with me?