@Tutanota

I have just checked it again with my own personal accounts and it worked this time. Perhaps thaey have realised they were not going to get away with it.

I will do another test with a friend where the emails are different.

p.s. there was also a recent change where gmail was refusing anything without an SPF record. I had to go through and update a lot of domains/mail account settings manually so they would work again.