Well, after endless hours playing jigsaw puzzles trying to fit potential
solutions into the space while not fouling or obstructing access to things
like the taps and the traps, I eventually settled on one of these in the
dishwasher standpipe:
http://tinyurl.co.uk/vhfl
....standing in for ...

http://www.speedplumb.co.uk/40mm-hep...ap-p-1573.html
I didn't have room for the 300mm recommended standpipe length above it, only
about 140mm, but it being a small dishwasher I reckoned and hoped it would
work, and I was right. However, I originally bought a second one for the
washing machine as well, and I don't think I want to try less than the
recommended clearance with a pump as strong as that, so I'll try and get my
money back on it, as they were quite expensive - £11.37 + £2.27 + vat.
Annoyingly, the recommended clearance was *inside* the leaflet, so I had to
open one of the packets to find out about it.

I've now done a dishwasher cycle and one and a half washing machine cycles
without any leaking whatsoever, so while I still hesitate to say that it's
definitely fixed it's beginning to look that way ... I guess a pullover
cycle with Dreft will be the ultimate test, but that will have to wait until
I start wearing them again in the Autumn ...

"Java Jive" wrote in message
. uk...

The most important horror is that, courtesy of the (lack of) workmanship
by
whoever installed the current sink plumbing, there is no fall between the
sink and the main soil stack.

I've now corrected that as far as the geometry of the cupboards would allow
without major surgery. It's probably still a little too low, but at least
it's in the right direction now!

So I'm now wondering if part of the problem might be that tea leaves and
other sink gunge is all washing back into the running trap for the
standpipes and partly blocking it.

The running trap stank to high heaven and its throughput was partly blocked
by gunge, but I suspect washing machine gunge, not sink gunge as I had
feared.

Thirdly, I'm not sure I was right about the Persil Auto, it's the auto bit
I'm unsure of

Still haven't checked this out ...