I had a ROLLEICORD II TLR Triotar 75mm f/3.5 a couple of years ago - lens was equal / comparable to my Zeiss Ikon Super Ikonta III 531/16 - Novar Anastigmat f/3.5 75mm. It was quite nice at f/4, but only in the center of the frame. At f/8 and beyond, the results were quite presentable. Unfortunately the R'cord had a few other problems - I gave it away.
Ian, I just found such european ad. In a british book from 1955 on photographic apparatus and materials. By London camera workshop Hugh Miller:
Aside the typical mechanical work, they recement, repolish and coat lenses