Basically need to run a HD cable to my loft, but it may be easier to use a couple of cat 5 or 6 as the smaller plugs may be easier to thred up through the wall void, and then put cat 5/HDMI couplings on the ends, anyone?

You can get video baluns to send video via cat 5. But if you are soldering on hd connetors anyway just use one hdmi cable? No? Or drill a bigger hole? And run data as well in case its useful?

Why make it more complcated than it needs to be?

An RJ45 isn’t really much smaller than HDMI though…

I’d make sure you get a decent cable by the way, I’m not sure how long a HDMI cable can reliably be, but ground floor to loft is probably long enough to cause some problems if the cable is crap.

Used one in the past, 30M with a pair of cat6 cables. Worked fine as far as I can remember.

I imagine threading one cable would be easier than two. Also rj45 plug plus a cable diameter is surely about the same or possibly even bigger than a HDMI plug for getting through holes?