No mention of + blu ray on HMV listing.
No, I need both discs and a 1 steelbook preferably.2 disc hubs showing inside the steelbook. The only definitive answer you're going to get is by possibly contacting Warner Brothers for UK releases.
You could try looking at other UK retailers for their Barbie 4K releases to see if they include a Blu-ray disc even if they aren't steelbooks if you really need to know that badly.
Or does it not matter to you and you were you just making chitchat?