Can anyone tell me where I can get a replacement for this broken plug into the TV from the sky box?

[KayBadge]

 

[Annie+UK]

That looks like a standard HDMI cable, you can purchase them online, or at many highstreet shops including Poundland, ASDA, etc...

[TimmyBGood]

@KayBadge 

You'll need to extract that broken element from the HDMI socket carefully though.

[TimmyBGood]

@KayBadge 

Actually, are you certain that was that an HDMI socket?  The label below says DVI (which is typically a computer monitor interface), and jamming an HDMI cable into a Display Port socket would definitely cause it to stick...

[Doc5907]

@KayBadge 

Something like the below HDMI cable will be suitable as a replacement..

AmazonBasics-High-Speed-Ultra-HDMI-Cable 

An HDMI cable should go easily into an HDMI port with nowhere near the amount of force required to break it as per your photo so maybe, as @TimmyBGood suggests, it was not the correct port, something to bear in mind when installing the new cable.