Wow a Brock - Now I see the Crystal Palace Fireworks connection!!
The compositions could possibly be analysed although I'm not sure who could undertake this and you could only get to the top layer. Possibly an easier way would be to find people with the original formula books - I think I know a couple of people who may have some of them. I'll ask next time I speak with them.
As kids we used to buy loads of the tiny Astra 2d Fireworks, as we had little money but at that price you could always be sure of having some fireworks to let off. We would get loads of the Green and Red Floodlights, Tiara Sprays, Daisy Sprays, Jewel Torches and the very thin straw like Magic torches and Fairy Torches. In all my years of collecting I have never managed to get my hands on the Daisy Spray, Green Floodlight or Fairy Torch, despite the fact there must have been thousands of them made.

I think the Brock's Box probably dates to the late 1920's / Early 1930's, particuarly as it is from the Sutton Factory which I believe closed in about 1935.
One of my other favourite boxes is actually a Brock's one. A lot of their fireworks (along with Wilder's ones) had the solid fuel mixture which I though was particularly good in fireworks such as the Burning Bush, Hornets Nest, Pixie Tree and Twinkler. The old fireworks had such wonderful names..............
http://pyrotechnics....org/files/brockAurora; Banshee; Catherine Wheel (2"); Crimson Cascade; Crack Pot (2); Elfin Spurs; Firefly; Golden Dust; Hornets Nest; Jade Jet; Roman Candle; Silver Cloud; Stella Electric Sparklers (7") Pack of 6; Tracer Stream Roman Candle; Tropical Storm; Vampire Bat.