Email Rendering

We have a 7.0.1 FP1 server and users with different clients, normally 5.12 or as we are in the middle of a roll-out, 7.0.1.

Users get an email from a certain company which will render fine in 5 but not in any other version, i.e. 6 or 7. I need to pin point why this happens and at the moment I can only come up with the fact they use style sheets for the email html i.e. www.companyname.com/stylesheet.css. Am i right in thinking 5 and 6 work differently with style sheets?

The email displays with a header ok then the main body is over to the right of the screen, then the footer is ok at the bottom.

I’ve looked at the way the email comes in but at the moment it looks to me to be the client causing the issue.

Any suggestions would be helpful

Thanks in advance

Scott