The fact remains that he doesn't seem to have a port 25 issue with the "home" ISPs, (I agree that that is surprising)
True, but I'm trying to provide a general future-proofed solution, that will cater for a homeworker joining the office whose home ISP is O2 or Orange et al.
but your idea when modified as I did does.
What is your mod to my idea? I don;t see it!
Or do you just mean have 1 a/c with authenticated BT SMTP for Home and other with UNauthenticated BT SMTP for Office? In that case it does not meet my criterion of future-proofing
1999: Freeserve 48K Dial-Up => 2005: Wanadoo 1 Meg BB => 2007: Orange 2 Meg BB => 2008: Orange 8 Meg LLU => 2010: Orange 16 Meg LLU => 2011: Orange 19 Meg WBC