Well the charming security guys turned me away when I arrived at 12:45, less than an hour late for my slot.
Really not happy as I was really looking forward to today - Heathrow should know well that delays happen. I know it's not their fault but it's not mine either when someone jumped in front of a train - especially when I've travelled from Suffolk only to have to travel straight back again, and pay for it all myself. There were plenty other people around me in the same boat. I was about to lose it with security staff and his attitude like "you'll have to get past me first" and refusing to talk to anyone on the radio, claiming they had no contact, so it was just as well that a member of proper heathrow staff came along and calmly explained the situation to me and apologised - he was a lot more reasonable.
Oh well.. I suppose better I missed the trial than my T5 flight tomorrow.. maybe.. let's just hope I get there ok tomorrow