Don't worry about work experience too much, myself and a lot of people I know had no experience of working in Pharmacy but got into university fine. The universities recognise it can be hard for young people to organise, if you have it it's a big bonus, but its not essential. In your personal statement just make it clear you know about how a pharmacy is run, what services they offer, things like that. I talked about minor ailment schemes and being a great alternative to the GP.
And what's all this about Natural Sciences and Biology and Computer Science? If you want to apply for Pharmacy, apply for Pharmacy! No back-up plans, no nothing, your back-up plan IS Pharmacy.
Please don't apply for Pharmacy if you're just "happy enough" to do it as a back-up. Find something else to do. Pharmacy is a vocation and unless it's your first choice, the thing you really want to do, then you ought to stay away. Why not keep your options open by doing a chemistry degree, or go into another field like law? Anything, just don't choose pharmacy.
Really good to hear you've got some experience early, make sure to emphasise that in your personal statement. I only got my first experience in a pharmacy 9 months after starting my degree haha.
You'll find a lot, if not all, MPharm courses have big asian student bodies. It's just one of these courses that attracts a lot of them. But there's a huge diversity on my course, a lot of Malaysians, but also Canadians, Lithuanians, Bulgarians, and I wouldn't focus on that too much
Durham University could be a good one to consider too, they look like they have a fantastically high standard of teaching and research.
And just to reiterate this again, Pharmacy is not a suitable back-up plan.
If you want to apply to Pharmacy as a back-up plan, forget it.
Only apply to Pharmacy if you're passionate and committed to it.