Hey buddy..
As you can probably tell from my username I'm one of the 'lucky few' that 'had the money'. Basically mate - the Pilapt is hard, but like with any hand eye coordination/aptitude tests, it really is you either have the ability or you don't. To be completely frank, I believe a lot of the guys that didn't get into CTC for whatever reason is down to how the afternoon session goes. The group exercise and interview! In the group exercise they're looking for calmness under pressure, good communication skills, being a team-leader, but not dominant, and of course, a team player. Basically everything required to be able to work effectively in part of a multi-crew operation. The interview is really there to question your motives. To make sure you are 100% motivated and determined to do the course. I can put my hands up and agree without doubt that this course is f***ing hard! And without continuous motivation and determination almost impossible!
Regards further education - I didn't. I dropped out after just AS levels at 6th form, and worked for 3 years as cabin crew before making the transition to cadet pilot. Obviously if you can get ahead of the game by getting an aeronautical engineering degree under your belt, DO IT! When it comes to Principles of flight and learning how a gas turbine engine works, it will be so helpful, and you'll breeze through most of the groundschool! But all I am saying, is it is not essential!
Finally mate, CTC take on average 3000 applications a year, and offer 5% of those 3000 places on the CTC courses. Courses run each month and vary from 12-30 students per CP. All the best of luck, and don't hesitate to drop me a personal message if you have any further questions.