However, if I try a 10 metre cable, the display cycles between on and off every few seconds.
Now, I'm not sure whether it's the length of the cable or if it's the cable's version. My shorter cables are most probably version 1.3 HDMI cables. The 10m one is 1.4 with ethernet.
I've read somewhere that HDMI cables with ethernet do not work with SlimPort. Is that correct? Should I order an older 1.3 version? I'm thinking 10m is a bit excessive anyway and I'll probably go for 3 to 5 metres this time anyway. But I didn't want to order one with ethernet and experience the same problem!