We're going to be removing all the themes with Tell A Friend on them soon, as they are not very accessible or display well on mobile devices.
We recommend everyone moves their site to Bootstrap or Modern theme. These themes have lots of display options so you should be able to find somethign that you like. They also work great on smartphones, unlike the other themes.
Of the two, Modern is a bit more "out of the box" ready and is what we use on the main Voice site. You can pick your highlight colour and change a few things.
Bootstrap is more customisable for different layouts but maybe looks a bit more plain unless you are prepared to configure it a bit.
We will be enforcing this change over the coming months to ensure that all sites meet recent accessibility guidelines. So if you change soon you'll be ahead of the game!
Thanks
Joe