So we did 'loosen and tap' and my level board was less like a saw tooth ploughed field today. So I have the spindle and carriage almost to vertical with .02mm. The Y axis is another matter. For now, I have made a level spoil board. FYI at X625 Y -400 or furthest point away from origin, the drop was 2mm!! Since I cannot have my machine out of commission I'll need to wait for the replacement before I have a go at sorting that one out!

Thanks for calling me out guys. I really ought to take more responsibility for my machine - this coming from a guy who once only had 6 oil changes on his 323 Mazda before it conked out at 145,000 miles!