So bought another bottle yesterday, and as the photograph illustrates, had a series of difficulties opening it. Was even reduced to searching websites when the cork initially refused to 'pop out' and found one forum where a group were arguing increasingly more aggressively in textual form - for what felt like hours - as to what was the best thing to do. When I tried some of their advice, which was to run hot water over the cork, the result was that the rounded top just pulled off. So then I resorted to a corkscrew, only to find that the one in this flat is one of those that has all the appearance of a corkscrew but is actually made out of metal-coloured mud, which just bent when I even showed it the cork, and then got completely stuck.
As you can see, this bottle remains unopened, and any suggestions as to what to do next are welcome.