Trusted sources for medicinal herbs
I’d recommend Napier’s the most, they are as far as I know the oldest running herbal store in the U.K. and they care a lot about quality and have excellent customer service. The delivery is very fast. Their skullcap tincture is fresh and potent which is a sign of a good herbalist. Urban Fringe also sell a good skullcap tincture and have good customer service.
A. Vogel is a brand widely available in the U.K. who sell many fresh tinctures, bit pricey, but good. The volumes you get are on the small size compared with Napiers. They sell through Amazon. Note though, Amazon is good enough for some powdered herbs off certain companies, but not generally good at all for tinctures. Generally overpriced and low quality. Here are some herbal stores in the U.K. I think are good:
Herb Pharm can be imported into the U.K. through iHerb UK, it is expensive as you have to pay for customs (add 2/3 to price), but quality is good and so is the range. Generally, people in the U.S. have better options for herbs as the market is far larger.