Unless you are lucky enough to be a newish Sky subsciber, you won't get get anything in HDR unless you want to cough up for a new box. In times gone past, i could understand that reasoning, because as the customer, you owned the box. With Sky Q though, Sky own the box, therefore you are renting the box.
They still insist though that to get an HDR capable box, you have to buy it from them. I wish that some crusading legal mind would put their mind to this crap and sort it out. In other words, why would you pay for a service you can't get because the box is so old it's not capable of receiving that service that any new customer would get by default. At the same time time, Sky want to charge an existing customer to "upgrade" to a box that replaces a box they are "renting" from Sky in the first place.