Here's the thing: British IPTV HDR to SDR conversion requires the IPTV reseller panel to tone map. The British IPTV reseller's IPTV panel receives HDR10 or Dolby Vision. For non-HDR TVs, the IPTV panel should convert to standard dynamic range. Most IPTV panels don't. They send HDR anyway. Your TV tries to display it. Colors are wrong. Brightness is broken.
In most cases, the British IPTV reseller has no idea this is happening. They test on an HDR TV. Looks great. Their IPTV panel settings say "HDR passthrough." They assume all TVs handle HDR. Non-HDR TVs get garbage. The British IPTV reseller blames your TV. The real problem is their IPTV panel missing tone mapping.
What actually works is asking: "Do you convert HDR to SDR for non-HDR devices?" A British IPTV reseller who says yes has configured tone mapping. One who says "all our content is SDR" is lying about HDR. Test on a non-HDR TV. If colors look normal, conversion works. If everything looks grey and dull, it doesn't.
The pattern that keeps showing up is this: British IPTV services that advertise HDR but don't offer SDR conversion are excluding non-HDR users. The British IPTV reseller assumes everyone has a new TV. They don't. A British IPTV reseller who offers conversion serves all customers, old and new TVs.
Take a real example. A British IPTV reseller sends HDR only. Your 2018 non-HDR TV makes everything look awful. You complain. They say "upgrade your TV." Another British IPTV reseller detects your non-HDR TV and sends converted SDR. Perfect colors. No upgrade needed.
Honestly, you can't add tone mapping yourself. The British IPTV reseller must do it. If your non-HDR TV looks bad on HDR channels, find another reseller. Their IPTV panel is excluding you. Don't accept "upgrade your TV" as an answer.
That said, some British IPTV reseller operators offer dual streams. HDR channel has an SDR backup. The IPTV panel serves HDR to HDR TVs, SDR to SDR TVs. No conversion needed. Two separate streams. Clean. Efficient.
The best British IPTV services for non-HDR TVs are those where you never think about HDR. Everything looks correct. Colors are right. Brightness is normal. Their IPTV panel handles conversion silently. You just watch.