I often have Monday am flights out of LGW that have me arriving at the terminal around 7am. I always use regular security because it is quicker than fast track and it usually is 10 minutes or less for the entire process. They are very efficient. I was there about a week and a half ago and they had closed one of the two regular security entrances, but were routing passengers around another direction and it seemed like the 2nd area (far end furthest away from BA/No 1 lounge) was still open but just had a new entrance.

I hate waiting at airports, but if I had checked in via the BA app and wasn't checking bags, I'd be arriving at the terminal about 4:45am.