I have no direct web link into offcial government webside however pretty much all UK bark online is powdered.No sourcing due to rules but look it up,I doubt anyone would be risking prison if it wasn't, especially when reddit is full of extractions going on.
Obviously it is only for dye purposes not for extracting
same applies for spores-for microscopy research only-live cultures illegal,spores not
cannabis-seeds for collective purposses,suveniere,cuttings/germinating seeds illegal
all analogues banned from 2016 apart from cigs/alcohol and prescription meds
the only thing still on is the 'poppers' sold in some corner shops as 'shoes refreshers'