"HDR10+ metadata missing." Your TV supports HDR10+. Your seller's HDR stream has basic HDR10 metadata only. You're not getting the full HDR experience.
Here's a short relatable scenario: HDR10+ has dynamic metadata per scene. Basic HDR10 has static metadata for the whole video. A British IPTV reseller who preserves HDR10+ delivers better picture. A seller who strips it delivers basic HDR.
In most cases, a good seller's HDR streams include HDR10+ where available. A bad seller's HDR streams are HDR10 only. A terrible seller's HDR streams are actually SDR tagged as HDR.
What actually works is asking: "Do you support HDR10+ or just HDR10?" A good IPTV reseller UK answers honestly. A bad seller says "HDR" — which could be either.
Let me give you a real example. A user's British IPTV HDR looked good but not great. His TV showed HDR10, not HDR10+. The seller stripped the dynamic metadata. The user found a seller who preserved it.
Most operators find that HDR10+ is noticeably better. Sellers who strip it are delivering inferior HDR.