I've figured out a little bit more on this topic to make it work better for my needs. Just in case anyone is interested...
My solution centred around having multiple 'member directory pages' and customising each of them. If you log-in as admin go to web pages, add new page, choose functional pages, and then 'member directory'. The advantages of this are three-fold: 1/ you can choose which membership levels appear on this new membership directory and limit it to those which are relevant for this page 2/ you can customise the columns on the keyword search page (so for example- I have links for my members to three different "member directory" pages now, each entiled a different search (eg. volunteer seatch, organisation search) each with different columns which are relevant to helping differentiate between that membership level. 3/ this allows you to incorporate a saved search with you might have made as an admin member
Assuming some people haven't yet cottoned onto this solution I hope this is helpful for making 'searches' work better for you.
I still think however 'advanced search', a powerful tool, which should be very useful to members is made overly complicated by the inclusion of items in the list which are not searchable by members or the public. Simply put if a database field is listed as "no access" in the default selections then it shouldn't as a rule be included in the advance search.