my DNS irule - how can i optimise it further or is there a better way?

Yet another thank you - When i was researching/reading about optimising rules, a few posts I came across said you couldn't use switch with datagroups as i was trying to avoid if/elseif/elseif/elseif/elseif logic as suggested, especially as the number of sites grow. But couldn't seem to find a way, this is exactly what I was trying to do and it means i don't have to create loads of datagroups for each different site. Looks like F5 could sell me a place on the irules course next :-).

Regarding the not well formed XML, it seems that comments don't cancel out curly braces - when i removed the commented line it works as expected e.g. this is what didn't work.

          if { [set FakeIPv4 [class match -value -- $fqdn equals site1_whitelist]] ne ""} {
          if { [class match $fqdn equals site1_whitelist] } {
                  Client made a DNS request for a Whitelist site.
                 set Whitelist_Match 1
                 set FakeIPv4 [class match -value $fqdn equals site1_whitelist]
                 DNS::return
          }
 

Regards

Adrian