I am sure that there are a number of people on here that can replicate the old british banger but I doubt any will tell you how
but if you trawl through some of the old threads you will get a good idea.
If I remember correctly some of the last ones made started to use flash and this led on to their ultimate demise
all retailers here sell fake black cats and bad boys... 2.5gr flash roughly small red tube... visco. wanna make these just different packing...