A possible solution could be to check out the work you lost out on and see if in your opinion the scaffolds complied with the current regs, look at your drawings and do they compare. Assuming that the client specified all tenders required a drawing, was yours over the top so to speak in material thus imposing extra costs, if that were the case I would be looking at a new designer. If all were equal however you should revisit your pricing structure and possibly design fees. However if the regs were ignored in the granting of the contracts thats another matter and is out of your hands, age old story, they'll get away with it as long as nothing happens unfortunetly.