Don't worry. All the work we do is through the post or via our online mastering system and we have loads of happy clients. Apart from the cheaper costs, think about the fact that you don't have to sit through a 10 hour session listening to the same 15 second section of your track whilst the EQ is being tweaked! Our engineers are vastly experienced and will know exactly what needs doing to make your tracks sound great. Just make sure you provide lots of notes and examples of other material if needs be.