Fifth image (20211014_141315.jpg) looks like it's mis-wired to me - looks like solid blue and solid green are next to each other on (respectively) pins 4 & 5. Though the image is a bit blurred and making it hard to see.
Check them again, the pin outs should be the same both ends and follow the order White/Orange - Orange - White/Green - Blue - White/Blue - Green - White/Brown - Brown.
If it is mis-wired, it'll need to be cut off an re-terminated correctly.
(And shame on the installer for not testing it properly, but we've all been there.)
I'll double check.
The fifth imagine is the end in the annex and as best I can tell it looks like two solid colors are next to each other but my eyes are having a job to distinguish the colors exactly.
Sorry about the pictures, I had a hell of a job getting them done with any sort of clarity some of the others were even worse!!
Would it being mis-wired explain why I had consistent problems with dropouts when used for it's original purpose of linking the sky boxes together? If thats the case you see I will ring sky up again and tell them the issue is still present.
I spoke to them a month or so ago and they just blamed my crap internet connection obviously that isn't a factor now I'm on fibre.