I did email them about this, the reply is below verbatim.
I'm very sorry, every starter kit should usually come with one as standard! I will have to chat to the guys in dispatch and see what happened. I'll send you one first thing Tuesday and I'll put in an extra switch and load free of charge to say sorry!
They are good guys, I asked for all switch and loads in my kit instead of the splitters and it was no problem for them.
Good point, I think my point was time saving in laying in cable, although as you know statutes/regs require us to use the least materials in an installation. You know its green and sustainable and so on.
I'd say the materials and energy put into manufacturing the boxes required on any job would be more than the length of cable they replaced.