Re: Is this a lost in translation
If the road you were travelling on changed speed limit such as going from national limit to 50 or to 40 then the sign MUST be visible or it is assumed without correct road signs that the speed limit did not change. If such a case where you were caught speeding came about, without you being able to tell that the speed limit has changed it is with almost great certainty that a court will find in your favour and throw out the case.
If on the other hand there was a sign fully visible and you were still breaking the speed limit, well that's on you. :-D
I personally ride with a journey camera now, so that if something like this ever came up, I could see on video if a sign was obscured and use this as evidence.
-SA