I ordered the single from a Portuguese seller, but he informed me that the wrong disc was inside the sleeve. As a consolation he would send me the sleeve for free. All I had to do next was buy the disc - and fortunately a cheap one without the sleeve was on offer by another seller. And so the set has become complete after all!
My collection: 7" single no. 6857
Found: Discogs.com, received 31 January (sleeve) & 4 February 2023
Tracks: 'Madrugada' / 'Entre Espanha e o mar'