Had a look behind me and under the bed, but couldn’t see any… Perhaps I should explain a bit further - I can find slats,  but not sure whether they’re sufficient quality, look good etc etc Im hoping that someone who has done this can share what they used, where to source them etc. Thanks !

Ah ok, Sorry – My bad english. Yes the slats the clamps are design for in the first place have to be 4mm wide. They can be easily found here in europe at Leroy Merlin. Seems that in other part of the world, 5 mm thick is more "standard". I think somebody worked on my design to accomodate it with 5mm wide slats. If this is the problem, here is the solution: download the right clamps for the slats available in your country. If it's a problem about sourcing them, I just can recommend to go Google. And also read the specific topic in detail: a lot of menbers have tried it from many country so maybe hints are here and there. About quality: I used cheap fir (christmas tree), no varnish, no oil, raw fir. They haven't moved for maybe 2 or 3 years now so you have headroom for quality.      

Many thanks Mat j'adore :-) Will do some more googling. Don't want to spend £80 or so and find out I've got the wrong bits.