Reddit mentions of Stewart 2143034 50 cm Multi-Purpose Saucer - Orange/Terracotta

You need:

• a plastic container to house them in. You can cut and mount some mesh screen in to the lid for air, mine are fine without though, they like humidity but you need to keep an eye on mold.
  
• Substrate (traditionally paper egg cartons, but anything cardboard can work, like paper towel tubes, even burlap. They love the crevasses in egg cartons though!).
  
• An under tank heating pad. They will live at room temp but they are most productive around 32C (90F) Simply place underneath your container.
  
• Food and water dish. I like to use ceramic saucers meant to go under plant pots (these things) because they're low and the thick edge means they can easily climb in to the food.
  
  
• Water crystals as a source of hydration (they will drown in liquid water). Don't bother getting the pre-watered "cricket quencher" in the pet area, get the bulk bags in the garden section (Link)
  *You can also rely on produce as a source of hydration, aka carrots or celery or whatever. Just don't let them dry out!
  
• Food. The food you use determines how nutritious they are. Table produce scraps are good but high moisture levels will mold so remove quickly. Finely ground dog, cat, or bird pellets work (I have birds too so I feed my roaches bird food XD). Companies also sell roach chow mixes. Remember that what you feed determines how nutritious the bugs are!
  
• Oranges seem to inspire breeding!
  
• Place the food and water on top of or next to but not underneath the substrate to keep the food free of mold.
  
• Poop will accumulate on the bottom. It's a good fertilizer so dump it on some plants :). I just used a spare tank screen lid to sift babies out of the poop when I last cleaned the tank, worked like a charm.
  
  Here's a place selling roaches that's in the UK! Google "dubia roaches UK" or something and check out what comes up :) If a place sells by weight and not number that is a better deal!
  
  Unlike crickets dubias are very slow growing, and they take months to reach adulthood. Figure out what size you want to feed to your critters immediately and buy those. Or, If you don't mind waiting, you can buy mature males and females but you won't have babies to feed off for a while, one to several months depending on the size you need. You can also set up 2 containers, one with ready-to-feed roaches and one where adults make babies and you leave them alone for a while for the babies to mature.
  
  Roaches are super duper IMO!!