I can only speak for the university I worked in, and all of the courses were oversubscribed, some only very slightly, some by 1:20. ACORN data is also considered when an offer is being made and personal statements and references go a long way to demonstrating interest and determination. For example, someone applying for a maths degree could join or run a school maths club or chess club at lunchtimes, or they could be a peer mentor for struggling students. Any activity that an applicant can use to demonstrate talent, interest, commitment, perseverance or determination, even something like having a paper round since 14 or organising activities with a local youth club or being a charity organiser all school all go towards demonstrating that little bit special that sets one application apart from another.
With applicants who have taken time out to work, whether a couple of years to save up or several years to work, that's not a problem, especially if your work experience is relevant to your course, but even if it's not, talking about relevant literature you've read, research you've followed, academics that spark your interest all demonstrate why you're applying for that course.
I've read some awful applications from students with all A* at GCSE and A level with no real passion for the subject or institution and I've read some brilliant applications that gave me goosebumps. Each institution will be different but it's the little things that stand out, and taking a gap year or a longer time out needn't be a problem.