Looking up the model is seems like a 2015 budget model TV, that would make it unlikely to have HDR.
Some TV makers patched in soft HDR support via firmware update but the benefits are dubious as you really need a hardware display capable of showing it.
If it has been patched in then you might have to enable it manually via some settings in the TV before the PS4 Pro can recognize it but there is so little info on this model and Hisense UK site is so barebones I couldn't tell you how I'm afraid.
This video show how to enable HDR on Hisense 8C series TV's if your lucky maybe it applies to yours too.