This seems to be the bit you need to set up Looks fairly normal and far simpler that the Cisco ATA
Subsequence Substitution: A subsequence of keys (possibly empty) can be automatically replaced with a different subsequence using an angle bracket notation: ?'. So, for example, "xxxxxxx" would match "85551212" and transmit "16505551212".
so in your case it would be
( 0 xxxx xxxxxx |00 xxxxxx xxxxxx | xxxxxx )
Or thats how it reads and how I woul expect it to work, As the first entry says anything starting 0 with 10 digits to follow send as dialed same for 00 but everything else dial 01247 before it. if that doesnt substitute correctly you may have to do xxxxx etc for 2 to 8