I didn't receive any posts in "IADB whitelist" thread from the OP because they all failed DMARC with a reject policy. I found the posts on gmane.
Posting to mailing lists with a domain using a strict DMARC policy is inherently risky because you are losing the redundancy of an aligned SPF pass and there's a lot that can go wrong with DKIM. In this case the open-t.co.uk DKIM signature signed "reply-to" and a lot of "list-*" headers that are added by the list. This guaranteed a DKIM fail downstream of the list servers. I thought it as worth pointing this out to avoid others making similar mistakes. However, DMARC problems could generally be mitigated by the listservers adding ARC headers.
