LG 55" B6 OLED £3000
Yamaha MusicCast RX-A3060 £2000
But my PC would be connected to the same!
Counterpoints...
Midrange:
Sony Bravia XBR-X900C 55" can be had, in many places, for $750-800. There's some light leak/uniformity issues, but this was Sony's flagship ultra thin, ultra hd option last year (and MSRP was around 2500). It's got a TON of bells and whistles (autodimming, etc) for the price, so judge the light leak by how much it bugs you in relation to that.
Yamaha RX-V481 does all the passthrough stuff you would want at between $300 and $400. 4 HDMI 2.0a/HDCP 2.2 inputs, ARC and other nice features that go with your wireless network/bluetooth/airplay needs. It's 5.1 only and no Atmos, etc. You can also upgrade to the V581 (7.1 and gives you back some of the stuff you lost) for around $400 to $500, and get back Atmos and DTS-X.
Budget:
LG 50UH550 50" is a solid set. It'll do HDR and 4k really well and has some more basic bells and whistles. For between $500 and $600, it's a nice budget option for HDR.
Onkoyo TX-SR353 for $250 - $300 will do your DHR and 4k passthrough. Again, it's only 5.1, and it's short on some of the bells and whistles, but for a budget receiver, it handles itself REALLY well.
And, this holiday season, I suspect (given what we're seeing for sales, NOW) that we're going to see options available that are even less than the above. It's actually NOT a bad time to start thinking about an upgrade. the 4k stuff is mostly marketing hype, but the HDR and new motion/artifacting algos are not. Good stuff came late in 2015, and it's quickly reaching mass market prices.