Vito w639 front shock absorber nut size

[Fewksie]

Hi all. Hoping someone can help. My top mounts on my Vito 111 are shot so I went to replace them but the nuts are seized solid. I've tried impact guns, long bars etc but can't get it to budge. So I'm going to break it off but I need to know what size the nuts are to replace them with. So does anyone know the size of the top nut on the front shock absorber on a Vito? Thanks in advance

 

[carat 3.6]

Those are M14, but can be 1.5 or 1.25 thread pitch depending on which brand they are.

You wont undo it with a bar as there is no way to stop the shock turning without damage, I've not seen one a decent impact gun cant remove.