Mains rated sleeving / sheathing for Cat5 in mains enclosure

["Jonathan Shaw" <semi.jon@xxxxxxxxxxxxx>]

I chose to use stranded CAT5e cable to help with connections in
confined spaces (it bends easier) there are a few cases where I have
realised that some network cable may not be separated from the mains
cable in an enclosure because of the way it is routed into the
enclosure.  Is it possible to buy 240V heat-shrink sheathing that I can
apply once I have routed the cable before connecting everything up?
Somethign like this looks promising
http://www.rapidonline.com/netalogue/specs/03-0100e.pdf
but the spec is a bit confusing as it states on this sheet "dielectric
strength 25KV / mm"  and on the related sheet Max V=600
This looks fine, but I am not really sure if I am interpreting the
sheet correctly or the IEE codes.

Thanks
Jon