lol @ the darlek comment
right i've finished it and tested it with various different sources of pressure.
Here's the finished prototype:
upon testing, i had to amp up the pressure in my cornelius keg to 30psi or 2 bar to achieve the same pressure i got with one nozzle at 15 psi. i believe that pressure to be enough to forceably blast off any sediment left in the bottom of any bottles we might clean.
i then decided to ramp things up a bit :evil: and connected it up to my mains... not really much different sadly

so then i got out my pressure washer and meaning business :twisted: but alas, i didn't get any more pressure using that either :cry:
so either two things were happening; the first is my pressure washer must be utter *****

or there wasn't enough size to the holes for it to make it a difference... ie i had reached the maximum flow rate through the holes.
i'm not wanting to make the holes bigger just yet as i believe that there's another problem... in that i'm having to pump 2 bars or higher for just 5 sprinklers to be at an effective force to shift stubborn sediment. pumps of higher bars get quite expensive.
the BIG problem right now though is the spread of the jet inside the bottle. as it's still a relatively thin stream it hasn't got enough cover to fully cover the insides of the bottle with solution.
so what i'm going to do now is experiment with one nozzle back down at 15 psi and see if i can get a decent spread by crimping the pipe as phil had planned (thanks for the idea mate, kudos to you :) )