Hi Lance, thanks for the reply.
I actually sorted it by converting the .mxf file to windows media player format using Youtube Downloader. A round-about way of doing things I know but it worked!
In answer to your question, I can’t select any other option other than the .mxf options when I go to render – they’re all there but when I click on one, the render button goes pale i.e. ‘it isn’t an option to choose this.’ Seems strange doesn’t it?
I should point out that I’m a total novice and may be missing something obvious here.