Just been reading how the riot police turned up to a peaceful rave in South London. Maybe the Crown Plaza should have said the travellers were New Age travellers. That would have spurred the plod into action. Either that or said they were black? Both would have got a better response.
To be fair, it seems this was a one off. It wasn't the hotel's fault and I'm not sure what can be done to prevent this happening in the future. I'm also pretty certain "HQ" will know.
I think the OP has dealt with this quite admirably and I find their comment about compensation refreshing.