Q.Growing ‘Holy Basil’

Mediterranean basil is easily available and I have successfully grown it many times; however, my enquiry is twofold regarding ‘Holy basil’. I first came across this herb whilst in Thailand. It is has an unusual flavour that cannot be replicated. Like so many Thai ingredients, it is readily available there as it grows in the wild under many different conditions–wet/dry/hot/humid. The closest I have come to trying anything similar was a ‘lemon flavour’ variety of basil, which unfortunately did not germinate. I was very disappointed; however, before I try this variety again, is it possible to locate and purchase the seed of the Holy basil plant here in the UK?