Chance of a Canadian High School student getting into top UK unis?

Written and posted from mobile, so apologies for bad formatting/typos

Okay, I’m usually not a big fan of chance me-ish posts, but the general requirements for Canadian students posted on UK universities’ websites are few and ambiguous, so I’d love to hear some past experience/insight from you guys. If that matters, I’m considered international in both CA and UK, so cost and stability wouldn’t be much of a concern, plus, I’m just worrying about chance of admission at this stage of the game. I’m looking for a physics major for the most part, but a more biochem approach is also probable.

I’m just ready to start my G12 (final year) in Alberta in a public high school with AP programmes. My current marks are:
Physics 20AP - 100; Physics 1 AP test - 5
Chemistry 20AP - 97
Biology 20 - 97
Maths 30-1AP - 98
German - 100 (is academic course, btw)
English 20-1 - 85
Social 20AP - 88 (not going to be included in admission)
Another AP 5 in languages, but I’d assumes it’s irrelevant
Top 5 AVG - 96

My goals in Canada are McGill, UBC and U of T which are relatively easy to achieve if I maintain my standards, but my real aims are Oxford (which depends on my PAT in Oct), Imperial College London and University College London, the latter two being the more realistic ones.

In the admission requirement pages for UCL and ICL, it is stated as a general rule of thumb that Canadian students do not require mandatory standardised testing; the course marks are what’s relevant. In UCL, the top 5 avg requirement for Alberta students is 90%, whereas in ICL it is stated at 85-90%. Now, I have learnt to not trust any of these average requirements from university except for maybe McGill, so I’m curious what marks, alongside my quite lacklustre ECs (UK unis are not big fans of huge amount of ECs thankfully) can get me into the said universities.

Cheers in advance