probably should read '2 way & intermediate', but one of the switches may be 2 gang (to control another light?)for using same cable to gas & water, normally done to what suits layout best. If you pass one to get to the other, use same cable. if opposite directions, one to each.
just remember not to cut the earth (must be unbroken)
for 2 or 3 core, probably what the college orders. sometimes 2 core, sometimes 3core. doesnt really matter which
