Sussex Uni CS degreeWatch
Your chances at being accepted onto those schemes are going to depend mostly on what your skills are like at the point that you're going out to apply for work. Their selection criteria will most likely involve a range of ability tests to check your analytical, technical and problem-solving skills, as well as things like your communication skills and how they perceive your overall attitude toward the job and things like your enthusiasm and willingness to learn.
Most graduates end up needing to pass through things like technical tests to check how well suited they are for the job, as well as a face-to-face interview which probes the technical skills listed on their CV, and usually a presentation and discussion about project(s) you've worked on - particularly the final year project.
The kinds of things which really help your employability as a graduate are being able to reach the end of your 3 years at university having acquired a solid set of technical skills and problem solving skills, along with a good, in-depth understanding of all the core concepts/principles. Also having a relevant 12-month industrial placement is extremely valuable since that's a really big opportunity to learn by doing the job, and provides a lot of good experience that'll put you in a much stronger position when you're applying for graduate jobs.