Thanks to the info on Answers i've copied and modified the lastlogin user macro to query Crowd.
This macro i have tested for a limited number of users/groups and it works fine.
When i expand it to query all users in Crowd (500) it churns away and eventually returns the error "502 Proxy Error - Error reading from remote server".
I feel this is a timeout issue of some sort. How do i overcome it? Thanks
Confluence 5.3