With the help of F5 support I have the following which does throw up the temp page and redirects but the full path is not maintained and that's what the user's want...
when HTTP_REQUEST {
if {[HTTP::host] equals {test-site.example.edu}} {
HTTP::respond 200 content {
The address you are attempting to reach is outdated. test-site.example.edu has been replaced by new-site.example.edu. Please update your bookmarks accordingly. You will be redirected to the new address in 10 seconds. Please click
here to go to the new address now.
}
}
}