I'd of thought as they are not overly expensive new, and they need a refurb and 1 needs welding.
(I say 'they' need a refurb, but that's down to how fussy someone is)
As in, refurb the single one to a new standard, and leave the other 3 alone, or just do them all at the same time, meaning they all look nice and fresh. Potentially costing around £250 with the weld work.
They possibly worth a couple of hundred squids.