If you are going to prepare for the UK theory test, you need to practise also the road signs. Here you can find about 660 UK road signs and free Road signs test.
Free road signs test
UK theory test contains also questions about road traffic signs. So practise also the road signs before you take the actual DVSA theory test. There are over 600 road signs, but you do not have to know all of them in the official theory test.
Here are some road signs tests, try them for free.
If you want to try the official DVSA revision theory test questions, you can find them from theorytest.org