Bad news I'm afraid the Gibraltar Museum have been in contact and have said that access to the Cave itself will no longer be possible. There is chance that we may be able to the entrance to the cave, however that is also looking doubtful on the day we plan to visit.
So I have been scouting for alternative options:Option 1:
At 09:30 The museum are still able to provide an introductory talk at the soon to be opened Europa Advance Viewing Platform, which looks like it is within the core zone of the WHS, I think at the location marked as 1st and 2nd Europa Advance Battery or 3rd Europa Advance Battery on the boundary map.
The viewing platform is in the WHS, at its southern boundary. From the platform you get a good view of the sea caves, of the whole WHS profile to the top of the Rock at O'Hara's Battery/top of Med Steps, and can also appreciate the now submerged landscape which was a sandy plain at the time of the Neanderthals. If it is boundaries which are of specific interest then it is actually a good place to go. The attached photo is the opening ceremony on the viewing platform, looking towards the rest of the site (right half of photo). WHS boundaries follow topography (cliff and ridge lines).
From here we can go back to the museum for a guided tour, and I'm working on getting a slightly more in depth talk/ presentation on WHS matters.
This finishes around 13:00 so I can find somewhere for a lunch for us all to sit and discuss the visit/ talk about future travels etc.
This leaves an afternoon free to further explore Gibraltar, or for those wanting a more in depth exploration of the WHS there is teh option to go for a hike through the landscape setting by walking the Med Steps Path, up from Jews' Gate or down from O'Hara's Battery (providing you're fit and have a good head for heights; but that also applies to the sea caves). There are also caves on this walk with evidence for early homo sapiens (also part of OUV), as well as a range of military heritage sites which have associative values, and good views.Option 2:
At 09:00 we can charter a boat that will enable us to see the Cave from the sea. And they can give us a commentary for this. The Boast tour last 1hr45min. Where upon we can make our own way to the Museum (perhaps I can still get the guided tour) and then carry on as with Option One.
The Boat tour would be an additional £425 (taking the 19 of us currently on the cave tour that would work out at around £22 per person extra). The boat however does have a capacity of 49 so more spaces are available if people would like to join. Though the same would apply to Option 1 as we would no longer be going inside the controlled military zones.
At the moment we have not been asked to pay anything for the Museum visit, though entrance fees are £2.
Right well any feedback on this would be appreciated, my personal preference would be for Option 1, and depending on how my travelling companions are feeling I would be tempted to go for an afternoon hike up to the Mediterranean steps for a further exploration of the core WHS Zone.
And secondly please accept my sincere apologies for the last minute change of plans, my heart rther sank when the museum contacted me and I hope we can still make it a worthwhile visit even without direct access to the cave.