I think Flavio uses Ogg Vorbis to compress wave data for “packing”. To my humble ear, Ogg is pretty doggone good for this job. FLAC is even better IMO…
D
Cheers guys. I think I’ve cracked it? Today, for the first time, on the same n build, I’ve managed to pack it way. Complete with wavs. I’ve zipped a and sent it. Now waiting for response. Fingers crossed…
Bingo! It worked 
I don’t quite understand why but it worked. Packed the song to the desktop, sent it to zipped folder and sent it - received ‘as sent’.
Thanks for your help people.