FWIW didn't like the lack of the central hubs penetration on the disc carrier with the two washers as spacers, so removed one, so only a single washer ~2mm in place. As much as I am sure it would be fine not worth the potential nightmare of the disc carrier breaking free.

Used angle grinder to place extra 'lower' adjustment slot in top cut height adjuster, took 5mins, super easy not sure if it will be usable given lower skirt height too but better than nothing.