I believe that at 310mm the shock is too long. Having said that, you might be able to fit different length dogbones to restore the correct ride height.Also, that top mounting point looks a bit narrow: again you might get away with fitting thick washers either side.
But what would put me off (apart from not knowing who the manufacturer is) is the apparent lack of damping adjustment beyond basic spring preload? There is no way the one single setting will suit light riders, heavy riders everyone in between as well as taking a pillion or catring luggage around.
Not a fan. It would get you through an MoT but for this price it'd be a miracle if it had the correct spring rate & damping rate to suit your weight.If you must get a replacement shock, keep saving and get something like a basic YSS shock, which at least has some adjustability.
