I took my test in Surrey, no need to bring pencils, rubbers, etc....
Bring your notice to appear, 2 pieces of personal IDs, PR cards, passports, Landing Papers and that's it.
You will be there for around 2 hours.
Test is easy if you study the book and online tests.
Do not talk to anyone once the test has started.
After the test, you will have an interview. Be careful and respond with clarity. This official is capable of denying your application based on your English knowledge will talking to this person.
After the interview, he will tell you if everything is in order and if your application is finally approved. They won't tell you when the ceremony will take place and them.
On my case, Test June 12, Ceremony invite july 24th and Ceremony Aug 12.
Good luck!!