Thanks. I have checked that the charset is set to UTF8 in all those instances but I still get problems. It seems that the only real culprit is double quotes that display as follows:
Most others seem fine:
Â¬ ` / ~ # , . ? : ; @ %^&*()!â€Â£$%
I set the field in the database that holds the email content to utf8-bin - is that correct?
Thanks again for your time.