Would be a failure, it's interfering with the swept area so would fail an MOT.
Would be an interesting roadside stop if the 5-0 insisted you remove it meaning you'd end up driving direct into bright sunlight.
I always worked on the basis that if I was stopped there'd be some understanding, that they'd see that technically it is illegal, but with it fitted the car is far safer than without.
Looks good Jon, like it all.