We use UHT milk so we don't have to heat it to kill any bugs. We also use a whole small pot of Yeo Valley per litre which seems to make it thicker. You may or may not need to strain it, depending on how long you leave it for. We have a piece of muslin cloth that we fold over & use to line a sieve & just pop it in there & let the whey (watery stuff) drain off until it looks about thick enough!
Easy yo isn't really proper home made yoghurt though, it's a powder you mix with water, which cost about £2 a litre. The normal yoghurt maker is just a litre of milk, with a spoonful of yoghurt as a starter, once you have made your first batch just save a little as a starter for the next batch.
Lakeland do a one bowl yoghurt maker, and you can buy spare bowls. I don't find it tart, if you want very thick and creamy like Greek yoghurt, just strain it. There is a brand called easy yo which uses a packet mix, which is a very expensive way of making yoghurt.