Last night’s “Britpop Night” on BBC4 was entertaining, but a little repetitive. I suppose that’s rather appropriate, actually, but even I was getting bored on hearing Inbetweener for the fourth time in the space of a couple of hours. I think the problem was that much of what John Harris’s new documentary had to say was repeated in the film that followed it, Live Forever. Both interviewed a member of Blur in the Good Mixer,…