[robbrooks]

Originally Posted by macafee2

Try a company such as https://www.allfix.co.uk/
or https://www.spaldingfasteners.co.uk/about-us/

you may well need a professional nut and bolt company, not one such as Screwfix

macafee2

Spalding fasteners look good - I ordered their left-hand threaded bar and nuts. Good postage amount too! Many thanks- it's a bit closer than central China!!