After all the main aim was to establish whether a candidate could do the job, how they would learn, what they'd bring to the client's company and how they'd interact with people. Nothing else really mattered. Fortunately the great majority of my clients felt the same way.

well, not to pick on you stales, but here is a perfect example where just making the initial subject (a candidate) into a plural (the candidates) removes all discordancy from a paragraph.