I've only tried 101 twice and it seems pointless and if I wanted to be cynical, I'd say the entire process seems to exist to discourage reporting (I imagine there's two ways to reduce their crime stats, one is to increase the numerator and solve more crimes, the other is to the reduce the denominator with fewer crime reports, and we can probably guess which is the easier of the two to achieve). Anyway, the first time I got a no-action letter (in the post) several weeks afterwards. The second I never got a response from. Similarly, attempts to report things online usually fail (Surrey's bad driving page, for instance, used to dump you at a 404, and I think more recently, call 101). It used to be possible to talk to the local plod, but now they ask that you talk to 101 first.
Longer term, of course, it ultimately discourages reporting. Life is too short, and it becomes someone else's problem.