hubert:
Obviously you had more luck with your request, I wrote an email to the Gibraltar Museum in early June, but never got a response.
Ah that is a shame, they were very quick responding to me, haven't heard back from Dolphin tours though, so it may just be the luck of the draw.
I will send of an e-mail, just to get a feel for a potential visit next year ad see what the come back with. Amazingly my 2017 is already filling up but September could well work.