Keep your eyes peeled around the start of Freshers, that's all I'll say
At Scottish universities, Scottish and RUK (rest of UK) applicants don't actually compete against each other, I assume due to differences in funding. So no preference is given to Scottish over English / NI / Welsh applicants, although they may have fewer spaces for RUK applicants than English unis have for home students.
Aye, don't blame you - is your commute still an hour and a half long? (Hope I haven't got the wrong blog there!) That's commitment!
Eh.. honestly, your job as an HCA will probably give a greater insight into the workings of a hospital / multi-disciplinary team / role of a doctor etc. than you'd get from your standard week of work experience, so write away! Obviously it depends on what you write, but I'd say HCA work is looked upon favourably. No real risk of looking like you want to go into nursing, unless you just write about your observations of nurses
Just the extended patient contact aspect of it is beneficial, IMO. As I said, I worked in a care home that was staffed purely with care assistants and nurses - not a doctor in sight, bar the occasional visiting GP. You learn loads just by interacting with patients.
Trust me, the UKCAT feels a lot easier the second time round. Although it's said to be an aptitude test, I went from 665 last year to 715 this year without much more practice - I was just used to the style of question. I honestly wouldn't think about it too much until after you've taken it - if you put yourself under pressure to get a high score, chances are you'll just get stressed out!