Floor is 100% not possible anymore. That's why it's in there - I completely renovated the whole ground floor (in such a way that it can't be taken up without ruining it) new electrics, and plumbing, but just put the wrong cable down.
It's deffo the cable - connected a longer cable above ground - speed back to normal.
Couple of routes possible - outside, up into roof space along to landing, down inside airing cupboard, down/into stairs and into the under stair cupboard. Or outside along and into hallway (might look messier on outside) through 2 door frames then under skirting(yet to be fitted) and under the stairs. Gaaaaahhhh
I really should have checked the cable. I don't even know why I used that one. The one I intended to use was upstairs. (Which does work).