I need to buy a test kit soon and I am wondering if there are any particular brands that are better than others. Also, what are some things that I should look for in a test kit? I know I need to test for ammonia, nitrites, nitrates, pH, anything else? Thanks in advance.
With regard to specific brands I'm not to sure on the brands you will have available over there (you'll have to wait for some-one from your side of the pond to chip in). However the range tests you have mentioned all are fine.
Personally though I wouldn't be too worried about the Ph one yet, unless you feel you have specific issues with your Ph. If this is the case then you are also going to need a test kits that measure Gh & Kh as well.
I would stick with the first three for the moment and save the money, unless like i said you feel you really need the others.
If you can get Tetra test kits, then they are one of the best on the market over here. Just make sure whatever you buy, you go with the liquid tests, rather than the strip tests. These are way more accurate.
I am happy with the aquarium pharmaseuticals liquid test kits, they are in just about every LFS that I've been in, I don't know if there is a better kit available, but haven't had any complaints. IMHO avoid the dip strips, I have yet to get any that work well.
I have both the dip sticks and the liquid kind, and the dip sticks work but they are harder to match to the color chart, so in that way they seem inaccuarate to me. The liquid kind is a lot easier to see, and I have the Tetra test kit. Also, the liquid is cheaper in the long run, as there are usually more tests in the bottle than the dip stick kind.