This arrived today, unfortunately I'm sending it back.
Firstly, it seems like a good cover and quality is reasonable. I'd expect it to last as long as, if not longer than the Oxford one. However, it's just not big enough with the top box on.
I'd be happy to keep it, but I decided that I use the top box almost daily and there's no point taking it on and off all the time.
Therefore I've sent it back and now ordering a L Oxford one with top box.https://www.sportsbikeshop.co.uk/motorcycle_parts/content_prod/101233
I think the M will do but the L is less than a pound more, so I'll play safe.
Here's a picture of the new cover on and compared to my old Oxford M.
I'll post some comparison pictures up when the new cover arrives, just so anyone else can see the difference.