Stepping off DLR 28 mins pre departure including checking in a bag and dropping off skis at the oversized baggage hatch is my record. Think I made security conformance by 1 minute so had to sprint up the stairs. I wouldn't recommend trying to replicate this though! 45 mins is my usual arrival time HBO. LCY is made favourite UK airport due to the ability to minimise time hanging around an airport & is only bettered in my experience by JL who have a 15 minute security cut-off with checked luggage and I have regularly arrived <30mins as their trains & check in experience are so reliable