Where can I buy mothers milk tea in UK?

Ra

I'm exclusively expressing and supply is going down. Where can I buy this? I'm not keen to buy online incase isn't genuine product. Any tips on increasing supply? I express 5-6 times over 24 hours for 30 mins. I have an electric pump on one breast and hakka on other and alternate this during expressing session. I have a 2 year old also so can't spend and more time than I do pumping.