Thank you everyone for your helpful advise. I did actually find a low cost program called PDFill pdf editor. It allows me to insert a video which will actually just insert a .wav music file so that works fine. I am trialling it now... so I thought I would post it here if anyone else finds it useful. Now I can use scribus to export my finished pdf and this program to add the music after. So thank you all for your helpful advise. I think the program is something like $20, so very reasonable.
Kind Regards, Heather
