Hi @stuart.yeates,
Thanks for posting! Are you seeing a lot of demand due to web crawler requests for the author search pages? If so, see Serious performance issue with regards to caching - OJS 3 - #9 by asmecher for some relevant suggestions. (These pages are deprecated in recent releases and will be removed starting with 3.4.0.)
Regards,
Alec Smecher
Public Knowledge Project Team