[celinego]

Thanks JSWolf

I don't think I can add zipped or RAR files into Calibre? Oh, wait sorry, I've just noticed it does have that option. Will try now.

Nope. When I add a RAR or zipped file to Calibre it automatically extracts the individual epub or mobi files from it. And if I click on an individual cover in Calibre it still shows the format as RAR but when I try to send it, it wants to automatically convert it to a mobi file (my chosen output format for my kindle) before sending. If I say "No" to the conversion, it just cancels the send option.

Or did you mean try sending a RAR or zip file via my webmail or emClient ... both of those DO still actually work when sending to kindle. Just Calibre that doesn't.