Hi Stu,
I prefer my Chord Active for use with SkyHD and yes i too can see an improved picture with better cables. I was recently impressed with the QED's effect on my brother-in-laws Sky HD box. I have found that all cables i have owned seem to need 'running in'. Never mentioned in reviews but my Chord was awful when i first used it, jumpy and blurry. Now its sharp and vibrant with great clarity of image.
The next cable up from your current one,the QED Reference can be had for just over £30 on Hificables at the moment. Great service they give too. Looking to get 2 for my BD player and amp. Thatcable is great but i intend to have these cables for years so don't see them as over expensive. Thatcable is still easily the best value accessory out there. Didn't check your spec but id add a Tacima Mains Conditioner before spending out on an HDMI cable. Removed much noise and added a warmer sound for only £30.
Good Luck