[bitfolk] Email - getting out of spam filters

Hello all, Wondering if any of you have experience with this. I have two domains, wiggly.org (A) and alertferret.com (B). A has been registered since 1994. B was registered very recently, within 6 months. I run email for both of these domains on the same server, otter.wiggly.org using Exim. I have the exact same MX and SPF records for both domains; @ 3600 IN MX 10 mail.wiggly.org. @ 3600 IN SPF "v=spf1 mx -all" @ 3600 IN TXT "v=spf1 mx -all" Sending email from domain A to gmail/hotmail appears in the main inbox. Sending email from domain B end up in the spam folder for both. Now, I am wondering why this would be seeing as there has been practically no email from domain B and therefore I find it unlikely that the domain itself has been flagged. All I can see is that domain A is a lot older but I have only recently added SPF and have never really had problems with my emails from domain A being consumed by spam folders. Checking a couple of blacklist checkers I cannot find my domain or my MX on any of them. Does anyone have an idea as to why domain B would be getting caught in spam traps whilst A does not? I have had someone suggest using mandrill or other external hosted solution but quite frankly if the mail is being blocked because it is being sent from domain B then that surely wouldn't give me any improvement? Any help, ideas, thoughts or further resources would be greatly appreciated. Regards, Nigel