Even better incoming CALLERID mods - guidance please!

I currently have the following code for chopping off the +44 from incoming callerid and it works fine:

exten => _X.,1,Set(CALLERID(num)=0${CALLERID(num):3:12})
exten => _X.,n,Goto(from-trunk,${EXTEN},1)

I would like to get fancier now! We get quite a lot of international calls coming in and would like to modify these differently (remove the + and add two 0’s). I have been playing with GotoIf but cannot get this to work correctly.

I would appreciate some help from the ‘dialplan gurus’ out there :wink: