It just struck me that I can't see the mail I'm responding to when I
click on reply. I only see what I'm typing.

Is it possible to make it so I get the message I'm responding to displayed beneath maybe?

Quote instead of reply.

email or message/post?

and yeah, on the top right part of each person's message, press 'quote' and you'll be taken to the reply page with the quote of the person inserted in your message already

for a reply to a thread just scroll down a bit, for reply to a PM, you could open up a new tab and reply there, or just copy and paste or quote in the new message.

It was PM I meant and the quote button is perfect, thanks!