This time it went against the window, over the double sink and it was a Grundtal 1200 mm 800 mm one. Which was a tad shorter than the sink itself which presented me with a problem - the gap between the sink and the wall was about 1cm smaller than the flanges I used to fix the uprights for the shelves, and there was a cornice at the top, and not a small one, either.
I used a 25mm flanges to fix the upright so to fit one of those behind the sink I sawed about 10mm off one side which was easier than I expected. They are made of a stainless steel, apparently, so I am not worried about them getting rusty. I did paint the inside of the upright, though, as they are only chrome plated on the outside.
The "cornice problem" I solved by cutting out a chunk of it with a drill, then masking the inside of the cutout with some cardboard ( I used an empty toilet paper roll and PVA glue :) and painted it white to match the ceiling. It now looks like it was meant to be this way, to a degree.
The other side of the shelf I fixed a bit further away from the wall so it is not quite parallel to the wall but I am happy with it. I think I am actually a bit sick of the straight lines in my kitchen anyway.
To drill holes in the pipes for the uprights this time around I used pedestal drill and a 'V block' which made it easier but I still managed to stuff up some exit holes a little bit. Also I decided to do without the dowel for the inside, it did not seem to affect the strength of the whole thing but this is just one shelf with possibly one more going above it sometime later, unlike my previous set up with four.
As a bonus I have discovered that IKEA's VURM 4-bottle wine 'rack' ( more like a bottle holder ) fits perfectly without any screwing just by snapping it under ( or on top if you wish ) the Grundtal shelf ( not shown on photo ). While you probably wouldn't want to keep wine bottles there there are alternative uses and I use it as a holder for a few sets of tall plastic Tupperware cups. That saves me some room in the cupboard for other things and they are easily accessible.
P.S. Ok, this is not an "instructable" but more of an example of what else you can do with shelves that were supposed to be wall mounted, this time setting those up against the window. I did not post step-by-step instructable as I believe steps would vary too much depending on your circumstances.