Some helpful tools for people looking to fill gaps in their Star Trek physical media collection...
The
Blu-ray Forum has a comprehensive database of releases. Here's
what comes up for TOS. In the upper search bar, you might see a US (or potentially your own country's...) flag. You can select Global to show everything instead. If I didn't yet own TOS, I'd take a look at this US
steelbook release... great price and packaging. Many Paramount complete series releases use cheap packaging where the discs are stacked and you really need to bend and pull the discs to get them out. Not good for repeat use!
Camel Camel Camel is great for researching an Amazon item's price history. How low has TOS gone during past Black Fridays or sales? Maybe if you wait a few months, you can get it for the same price. If you want to avoid Amazon, Walmart, Bullmoose, Deep Discount / Movies Unlimited, and plain old eBay are competitive alternatives. Rarewaves is a good alternative to Amazon UK. JB Hi-Fi from Australia has twice annual two for the price of one sales that can make the international shipping worth it. For a deep dive, the Blu-ray Forum has sub-forums based on retail and promotions.
The standard releases in the US, UK, Australia, and Canada etc should all be effectively identical in disc content. TOS on BD came out in 2009, and uses the very dated VC-1 codec, low bitrates, and DNR (where the picture is smoothed over to remove grain, thus also removing fine detail). One reason to buy the Roddenberry Archive (if it's cheap) is to get many of the best TOS episodes in much better picture quality.
The only version of TOS on BD that I know of without the original effects is the
Origins release (and you'd only buy that if you'd want the remastered "Where No Man Has Gone Before" and "Errand of Mercy" in AVC codec without DNR).