The HMV price was very good. A new 4K film usually sets you back around £24.99 RRP. So £28.99 for a steelbook included as well, is great. I'm not the biggest fan of steelbooks as they can scratch and dent easily, but it's the only option at the moment if you want a 4K version without all the bells and whistles.
If you're an Anime Unlimited member, it does bring the price down to around £31, which is still pretty good too. Plus, they ship using bubblewrap in my experience, so I don't mind paying a few £s more.
Amazon have the steelbook for around £26, but unless you have Amazon Prime you can add on about £4 postage to that, also Amazon UK packaging is literally a cardboard envelope.
Sounds like you've made the correct decision. Amazon are a scummy company, but my God, they know how to provide customer service and get things to anywhere in the world seamlessly.
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Anime Limited have also made a point of stating that the bonus disc is fully subtitled: