Ok some progress. After upgrading to latest version of Buddypress (released the other day) I got an error “expected to be a reference value given in” in plugin.php.
A quick search through bp-member-filter.php reveals line 265 where the function causing the error is called:-
function bp_replace_members_filter( $has_members, &$members_template ) {
Removing the ampersand fixes the problem, don’t ask me why as I haven’t programmed in over 10 years and am not overly familiar with PHP anyway.
To spell it out the line should read:-
function bp_replace_members_filter( $has_members, $members_template ) {
So pros:-
It does work with some fettling.
It beats writing your own search function from the ground up.
Cons:-
No one seems to be able to support the plugin (the author is awol as far as forums are concerned).
The documentation doesn’t go nearly far enough.
It won’t work with check boxes (yet) so have had to change a field to radio button (and temporarily change back if user profile needs changing)