Chromecast Ultra (HDR and 4K TV) £54 Argos
The Ultra version of the Chromecast brings a simple to use 4K & HDR source to your 4K HDR telly. The most important aspect is that it's a device in active development which might not be true of the 'smart TV' apps built into your telly which versions of Netflix, iPlayer etc may be languishing behind.
Looks like Argos are price matching Currys PC World who dropped their price overnight. Seems to be a lot more stock around.