Weird question, but I'm sat in a Mk 1 right now (4994) that has a seat moquette of regularly spaced black squares on a bluey-grey background, with random black squares having red lines at the top. I'm curious as to when this moquette is from, etc. While I have found a few things on the internet, especially the Bluebell Railway's guide, they're all quite limited and none of them have this moquette. Does anyone know what this is and, more generally, if there is a good reference (online or otherwise) for identifying seat moquettes (preferably both pre and post privatisation)?