I think there is a flaw in the general thrust of this question which makes it completely unfounded. Your generalizations are basically full of huge misconceptions which leave huge problems with your question. I will comment on some of the generalizations here which aren't really even true for the United Kingdom. If they can't be argued as true for the UK, then they cannot really be argued as a common feature between the UK and the other Commonwealth states. If not even the UK shares these similarities, how can they be argued as to be any more different or the same as Canada is?

1. Education: We do not have year-round schooling in the United Kingdom and never really have. The school year begins in September (generally around the 6th), and it ends mid-Summer.

Residential colleges in the UK are an extreme minority, only existing at a few of our 154+ universities. Maybe below 10 of them have residential colleges. We may very well have as many universities with residential colleges as Canada, or incredibly close to the number.

Undergraduate degree lengths differ significantly based on what subject you are looking at. Most arts degrees, like history, politics, languages, etc., in England last 3 years, however technical courses can often go 4-5 years and might come with a sandwich year in industry. The generalisation becomes even more shaky when you consider that Scotland does not follow the same basic principles as England, and generally a lot of their degree programmes are not 3 year BA/BSc degrees, but actually undergrad-masters degrees which last at least 4 years, resulting in an MA/MSc. So, again, the example you give here of the United Kingdom doesn't really apply well when actually looked at beyond the surface level.

The structure of a curriculum differs greatly depending on which university you go to. For example, my university suggests you take one specific module each year, and then gives you freedom to select your other modules based on everything you could possibly meet the criteria for. Smaller universities might offer a more limited scope of options, but generally I find this is the case with all of the ones I have looked into.

2. Sports: Rugby and cricket is kind of a great reduction down to only what the grouping of nations have in common, ignoring everything which falls outside of those parameters. For example, the largest sport in the United Kingdom is football (association soccer in North America), the participation in which (and the money involved) dwarfs that of cricket or rugby combined.

Similarly, Australia shares a similar trend with their own national game, Aussie Rules Football, which is not the same game as British soccer at all. I think most UK footballers might die in the average game of Aussie Rules, and that is before they even get onto the pitch. Again, this dwarfs participation in cricket and rugby combined.

3. Nomenclature: Tylenol is a brand name. We do not use that name because we simply do not have that brand. Additionally, in the UK we do not use the brand names Paramol/Panadol. Again, because they are brand names. The National Health Service generally prescribes generic drugs (ie, unbranded, non-copyright drugs), which is why the common language is in generic terms in the UK.

However, this is not a feature we share in common with South Africa, NZ or Aus. The nomenclature for medical terminology is not decided by some shared cultural history between our nations, it is decided by our institutional variance which forms a path dependency.

Does the nation in question provide nationalised health service? How does it source the medication? If there is a nationalised system, is it built upon universalist fundamentals or is it an individualistic career structured regime? What is the degree of stratification and marketization in the system?

These are all incredibly important questions, because they will effectively dictate the form healthcare in a nation takes, and thus the language that is used. For example, the UK NHS operates on a universalist basis with low stratification and, since the 1980s, a middling degree of marketization. This means that healthcare is free at the point of service or close to it for all in the United Kingdom, which forces the NHS into opting for generic drugs to lower costs. This is why our language there differs from your own.

The other nomenclature you mention at the end are all terms which also see use here from under the Canada section.

4. Other: We have both a strong tea and a strong coffee culture here in the UK. We might be more identified with tea, but it doesn't mean we lack coffee. Additionally, afternoon tea with scones and such is a fairly large stereotype which does not really have much founding in the modern day United Kingdom.

Basically, a lot of the examples you list do not really hold up under any level of scrutiny. When formulating this question, instead of looking where this grouping of nations differs, you went out of the way to look at what we share which Canada does not, ignoring contrary evidence or significant examples which might disprove your basis. In your search to set out the case that Canada is different from the rest, you forgot to investigate and scrutinise whether the UK, Aus, NZ or SA are really similar. Basically, your question set out the case that Canada is different before you knew if the rest were not also different and distinct cultures.

Do you have sources for these statements? I am Australian and maybe a third of these statements do not accurately represent Australian culture as I know it. For example: tea culture being larger than coffee culture, courgette instead of zucchini, the use of 'trainers', and the description of our education system etc.