Image is of SWA cable, BASEC approved.
http://tinypic.com/r/2j1lamr/3

Brown, Blue & Grey insulated cores show the copper "grinning through"
to the extent of being shiny at regular intervals along the cable.
Black & Gr/Ye insulated cores show marks, but no copper "grinning
through". Depending on where you exposed the bedding you would not
know, however the idea is the cores are *continuously insulated* -
oddly enough.

Yes it will probably pass a 1kV IR test.
Yes most face the inside of the bedding, rather than facing the armour
- but not all do.

Sigh.