Stay off the beer at night would be my best advice. It's a pretty intensive course.
Some training providers will send you some pre-training info to read. Pay attention to what is taught, study the material given and ask questions if you are not sure. Lots of questions.
From memory there should be 4 practical exams, and 1 online test. An Exd/Exe lighting install, an Exi instrument install and inspection for each. Lighting install will be a couple of glands in SWA with 1 barrier gland
I'm not sure if for the 5 day you need to do the equipment selection or not (choose JBs, glands, switch, light and instruments for an install).
The online is 60 questions in 2 hours. Tough, but they should provide you with all information needed including some multiple-choice questions to practice. The 60q exam is open book so if you practice the review quiz you will be able to quickly locate the right pages. Answer what you know first, then go back and search the rest. 2 mins per question is tight if you need to search all.
Another resource is the Facebook page "Compex Electricians" - they have mock exams in the files section. Join the page.
Retests are around ÂŁ75-ÂŁ150 per section, depending on the provider. Another reason to study and work hard. My mate failed the online - Asset in Aberdeen wanted ÂŁ150 for the retest. He got it at Falkirk for ÂŁ75.