memory?.....lost it years ago.
I keep a copy of Safety Sense Leaflet 6b Aerodrome Sense in my flying suit pocket all the time, open at the pages with light signals and signal square markings - very useful when visiting Old Warden!
Seriously, the only way to effectively remember things is to use 'em, and unfortunately, nowadays, few light signals are used. I know that when their use is briefed at Old Warden on display days, a sigh of terror can be heard from the visitors, until they realise that a crib has been strategically placed on the briefing room wall!
Good luck in your quest!
A