Feeding

the good stuff willb e pretty generic as far as likely ingredients. I'd find a 3-part system part a is some base with npk and secondary/trace elements a couple other parts can vary.. cal-nitrate + epsom, or something else nitrate with a different thids simple component for calcium etc etc.. so many variations possible. they key is a few parts that you can isolate and manipulate it for certain plants that don't fit the one-size-fits-all instructed values... when you see a toxicity or deficiency, you can adjust ratios and fix the problem. it should be dry and you mix it -- saves money, stores forever and a day, buy in bulk. get a agricultural brand rather than a "pot" brand. you'll save money and get better products most times. (don't use miracle gro, lol i'm sure you knew). i don't know brand names available in the uk.

There's plenty of online shops where you can get the basic nutrients to grow in UK. you'll find the starters pack from BioBizz for example at a decent price, provides all you need until the end. one stop grow shop - you'll get it home for like 60 quid the day after ordering

Are you using a Supersoil with added nutes? If so it needs nothing for 3-4 weeks. If not a 1/4 str feeding of general hydro flora trio works good and should be available. Happy growing!