Hi, so I have an update on this now.
Bit of background info, I took my car into the dealer a few months ago to be told there was nothing that could be done. Went back to dealer yesterday to be told the same story that the dealer know its a problem but there wasn't anything they could really do. They reckoned Skoda said it was a 'characteristic' of the brakes last time they contacted them about it. We had a good discussion and agreed the dealer would contact Skoda again with a video of my car making the horrendous noise.
Pleased to say Skoda have got back to the dealer yesterday and now admit there is a problem with the rear brake pads. Skoda are now fitting a redesigned pad that doesn't make the howling resonating noise. So my dealer has ordered a set. Unfortunately they are out of stock and on back order. But now at least I know it will be fixed. Hope this helps all the frustrated Karoq owners out there. I have to say we love our Karoq 1.5 petrol auto. Brilliant all round car... apart from the rear brake noise when reversing!