Well my dear ladies, I can happily lay the puzzling to rest! It was I who bought this bag on Monday, and after reading your posts I had a very sleepless night ... had I been a silly billy? I had as you could see, asked if there were marks on the front corners, but seller said very slight.
So I waited with some major trepidation, but the bag arrived today and I can report that there is no scuffing to the corners of this bag. It is in lovely condition, there is the tiniest dark spot on one side but it looks worse in the photo than IRL where you really need to look hard to see it. Apart from that, nothing, no marks, scuffs or anything, and the inside looks like it has never been used! A good colloniling at the weekend and then she can go into her dustbag till winter is safely over!
So I am one happy bunny - I think sometimes the high quality images pick up reflections etc which look like marks. And when we are spending hundreds of pounds it is nerve wracking, but thankfully this story has a happy ending (and my black SBS has a new friend)!