I think that some of the ladies were wearing 'holiday- inspired' [short and tight] rather than beach wear.
Here's an interesting thought - speculation please note - on my part. I know the Goring quite well - it's quite a popular venue for people attending events at Buckingham Palace [Garden parties, Investitures etc]. It is quite interesting because it is very traditional English, rather 'old fashioned' and 'correct', if you like. It's not 'over-stuffy; though - when I stayed there once, in my bedroom there was a lifesize sheep with a genuine woolly coat - a 'touch of fun' if you like.
And so I was a bit surprised to see that the Goring had opened a Mustique inspired Beach Bar. Belive me, until I read this, I would never have associated The Goring with Mustique. Whilst at one stage Mustique was felt to be 'proper' when it was the haunt of aristocrats [Lord Glennconner who founded it, Patrick Lichfield who had a villa there] and even Royalty [Princess Margaret had a house there, Les Jolies Eaux], over the years Mustique had started to lose its Cachet [Lord Glenconner sold out], Princess Margaret died, and a very different 'set' started to 'take it up' - basically, many [not ALL] were the 'vulgar rich' etc or 'International White Trash'.. in other wordsm the 'raffish' set. I am theerefore a bit, well, surprised to see that The Goring is going 'all Mustique'. Sorry, this does not look so dramatic in writing - it's like discovering that your favourite great great Aunt is an habituee of Studio 54 or whatever the current New York hotspot is nowadays. Which leads me to my next unprofitable thought - I wonder if the Middletons [very fond of Mustique] suggested the collaboration to The Goring and vice versa - in other words, acted as fixers, to the mutual advantage of both the Mustique Company [that owns the Island of Mustique] and The Goring?
This, if true, [and I must stress that I do not know whether it is true] would presumably have had a cash value to the businesslike Middletons....
Just a thought,
Diarist