Last week we were on holiday in London and my wife graciously consented to us visiting Kew. Whilst we were there we saw a tall Iris in the lawn beds that looked jet black from a distance. Close up we could see the flower was a glossy very dark purple. The plants were about 4ft high with large flowers. We were both very taken with them and would like to obtain them. Unfortunately they were not labelled and there were no staff about to ask. I did not have camera or mobile with me so have no picture. Anyone recognise this variety?