Ok, I have managed to work this out, after a lot of work! Basically Enta put the DDI number in a custom header called X-DNQ (don't ask me why and the current tech manager doesn't know either) but it is.
So I was able to add the following to sark_customer_extensions_globals.conf:
[from-custom]
exten => _.,1,Goto(mainmenu,${SIP_HEADER(X-DNQ)},1)
In case anyone happens to come across the same issue!
So I was able to add the following to sark_customer_extensions_globals.conf:
[from-custom]
exten => _.,1,Goto(mainmenu,${SIP_HEADER(X-DNQ)},1)
In case anyone happens to come across the same issue!