There’s a special thrill to watching an improv show, perhaps because the risk and danger is more obvious than it would be in a scripted show. When it all comes together it’s glorious – a magic trick that’s no less impressive just because you can see exactly how it was done. Any Suggestions, Doctor? sometimes achieves those glorious moments of collaborative sorcery, but just as often the spell fizzles out. It’s hard to keep an improv plot on track – and draw it all in to a satisfying resolution – at the best of times. It’s even more of a challenge when the theme is Doctor Who, and wibbly-wobbly timey-wimey complexity is the order of the day.