don't "chocolate blocks" (I assume the OP mean "boxes" not "blocks")
count as an enclosure ?

No, because at that point the cable only has one layer of insulation
for
protection - the outer sheath has been removed.

if not ten what else should I use to extend cables ?

A junction box is the usual way. However, if you wish to use choc
blocks,
you could simply put them and the cable inside a suitable box.
'Adaptable'
boxes - available from your wholesaler would be ideal.


ahhhhh... that's where the confusion comes in, I refer to junction boxes
(with the twisting top) as chocolate boxes (because they're usually
brown although lately I've only been able to get white).

LJ