We know, because we're folkies, what the *good* tradition of blackface symbolises. That is not true of everyone. Gravesham is one of the most ethnically diverse boroughs in the UK, including London Boroughs. In their own minds, the school are worried that offence would be caused.
I think they are wrong, I think that if the side gave a humorous and informative introduction to the blackface issue then the community would be find it fascinating and enjoyable. I grew up in the borough and went to school in Gravesend and speak with some personal experience of the local community.
However, I can understand the school's perspective. If you read [our own literature] about the origins of blackface and look at the contemporary language used by some of our sides [who talk about "Niggering"] then I can understand why a public, community organisation would decide not to take the risk.
Against that complete backdrop, why do we not celebrate our tradition just as effectively and authentically with a different, less contentious colour?