When booking your test, either theory or practical, it is important that you go to the DSA website, which is on www.direct.gov.uk. If you google driving test, it will give you two or three different sites, these sites will charge you a booking fee of sometimes more than £20.
At the moment this is the link to to book your driving test www.direct.gov.uk/en/Motoring/LearnerAndNewDrivers/index.htm
When you go to either test you must take your photocard as you will not be able to take either test without it. When you go for your practical test you must also take your theory test certificate.
The theory Test centre in Worthing is at Chatsworth House (first floor), 31 Chatsworth Rd, Worthing BN11 1LY
The practical test centre is in the Lancing industrial site 5 Chartwell Rd, Lancing BN15 8TU