Thanks for the feedback. I'll be looking at the alternator on Monday.

Replacing all vacuum hoses and PCV valve will often reduce these nuisance 700 range codes. Experienced a 471 recently and after checking electrical system, found low alternator output and excessive alternator ripple voltage. Changed alternator and fault did not return.
Maybe just a coincidence, time will tell.
Have also noticed the faults become more frequent with engine age/hours.