Ann: Half Yearly Report and Accounts, page-26

All I see here is the continuing trend of increasing the barriers to entry for small operators, and "back yarders", which only plays to ARB's strengths. I may be wrong, but I think what you are referring to is not really applicable to ARB, for similar reasons that it is not applicable to the vehicle maufacturers. I think what you refer to is more applicable to one-off, or low volume, modifications. Someone with sophisticated engineering capability, not just an angle grinder, welder & a hammer, but also design, simulation, development and validation capability, should simply be able to demonstrated compliance to the source ADR's. I suspect this will require very little discretion from the "signing engineer", but will be based on demonstrated compliance via prescribed test or mathematical simulation methods.