If I understand the history of the song properly it was Ronnie Browne who did a lot of the publicizing of the song as a possible national anthem after Roy died. Possibly the copyright rests with him as well. Ronnie has put out a CD called Battle Songs and Ballads on the Scotdisc label. The CD had the street address on the back BUT the web came through again. Searching for Scotdisc gave me a site with the addresses of ALL the UK recording companies. The entry was as follows.

SCOTDISC (BGS PRODUCTIONS LTD)
Newtown Street, Kilsyth, Glasgow G65 0JX.
Tel-01236 821081, Fax-01236 826900

They may be able to answer you.

Frank Phillips