I presume you mean 'never' have to replace them again?This why I went hydraulic when I bought my 2 post, I like the fact the threaded units can be bumped up very gently but you are tied to bespoke parts.
The way I look at it is it may cost you £800 to get it going but for home use you'll need to replace them again. Either that or you do without a lift or spend money on another secondhand lift that may also have it's own issues.
Have you tried talking directly to Tecalamit in Plymouth? They took over/merged with Laycock. I've bought parts for my Laycock 4 post and they were pretty reasonable
Yes, edited nowI presume you mean 'never' have to replace them again?