I'm not familiar with Scottish education so may be wrong here, but your education should be in order with the most recent first (sorry if they already are!) Your A-levels (or equivalent) are much more important than GCSEs, so should go first. You don't need to list every grade, for GCSEs I just put x number of As (including maths and English), x number of B's etc, but to fit your personal qualifications. Higher qualifications can be put on the same line, e.g. A levels in Biology (A*), Maths (A) etc, again changing the details depending on your qualifications. The education section should only be around a third of the CV, even if you have little work experience, and is the main reason why your CV is too long.
The rest has been said above basically - write what you did in each work role and what transferable skills you learnt that might be relevant to tech. I can't see it (but just skim-read), but have you put your software engineering study on it? If so, you can go into more detail with that e.g. particular modules relevant to tech.
If you can, try to get some tech-related experience, even if it's just joining a society (which you can still put on your CV if you actually did something there).
Interests are too long. Only needs to be a line or two. If you can, try and add something relevant to tech (e.g. 'taught myself to code with X language' or 'enjoy building websites' etc. I didn't even read the interests section, and I've got way more time than an employer would! Most your achievements can include just the title without a description. Take out the ones less relevant or impressive.
I have a personal statement section at the top of my CV, so don't necessarily think it needs to go or be called something different as someone else suggested. Make sure its relevant to tech/the role you're applying to and not just generic. Basically, you should be able to tell by looking at a CV the kind of sector the person might apply for.