I will, if I can get enthused enough to take the U brake off again and re-fit the Maguras. After a frustrating afternoon I put it all back the way it was !!
If you look at your photo of your set-up you can see the problem - because the adaptor is fitted upside down it fouls the brake cylinder where the hose connections are. I can't even get a little closer to the rim by setting the whole brake assembly at a slight inward angle, as this then brings the brake pad up against the tyre sidewall. I have the adaptors as far down as the slots will allow them to go.