I've just looked on Google Streetview. Admittedly it's a bit out of date but "LOADING ONLY" is clearly written on the road surface alongside what I believe is the lay-by you are referring to. If you feel the signs are not obvious you can appeal - in Reading, where I live, the council had to refund a lot of parking fines a few years ago because the signs were deemed to be "not clear". If you do appeal it's worth saying that you are new to the area and moved immediately you realised it was a loading bay.
Incidentally, you say the signs are 10ft in the air and the wording is tiny, so no-one could read them without getting on top of them. You then go on to say what was written on them - how did you read it? Be careful what you say at an appeal, if it comes to it.
I think I'm correct in saying that an appeal "freezes" the time before the £100 fine becomes payable.