Ah, didn't know about the siphon thing. It is one I bought from my merchant, standar traditional looking siphon in the original cistern flushing a full 9 litres. I t all appears to be working as you'd expect however I can't vouch for how much power it produces. Like I said, it's a (probably) 1970's low level Royal Doulton pan and cistern set up that I removed, cleaned up and then fitted with a new flush pipe and siphon. I didn't realise you could push the pipe too far in so I could remove it and cut a bit off the end (don't want to move the pan really, new bathroom/tiles etc). I could also change the siphon if there is a recommendation for some having more oomph than others? The one I took out was a big old red thing with a knackered diaphragm!