That all changed last night . . .
A single glass of red wine goes a loooooooong way. Wall, carpet, side of my chair all got a dowsing (I swear there was more liquid than was in the glass). The glass, believe it or not, didn't break. I can confirm, however, that white wine does indeed help take the worst of the red wine stain out of the carpet! Not all of it, but it looks a lot better. J has rewashed it with ordinary detergent, as we don't have carpet cleaner in our house, so hopefully that will take some more out.
It could have been worse (see, I always like to find the silver lining) it could have gone forwards into the really visible part of the room, rather than backwards, where to an extent it's hidden by the table and up against the skirting board. The chair is slightly patterned (and we think must have been Scotch guarded), so really any stain that will remain on that, will indeed just look like part of the pattern. And again the wall (although that does look to be clean now) is behind the table and fairly low down (and I don't think many people walk into t a room and start examining the wall and carpet behind a table/chair, do they?)
Oh, well... As I said, it isn't bad in all the years. As J said 'just don't make a habit of it'.