Thanks for offering to help. I'm trying to get the IKE log. I just cleared it to generate some clean log but now nothing is being generated which is odd. Anyway, three configs attached:
1. SRX210 working config (static end. The box is in front of me)
2. SRX100 working config (dynamic end. The box is 7000 miles away)
3. SRX300 failed VPN config (meant to replace the SRX210)
IKE log to follow when I can get one. Cheers
P.S. I'm afraid I am a Junos novice if that's not already obvious 