Our two favourite anchorages
, over a period of about 10 years, were Caleta Partida and Ensenada Grande. In July, both will likely be subject to Coromuels. We were never there that late in the year because of heat but in May/June, the Coromuels were a nightly feature. On the bright side, there won't be many boats out there in July and you might be able to find a flat spot.
Some people anchor
on the NE side of Caleta Partida to avoid the Coromuels. We have never tried that so can't offer an opinion other than "hear say".
The chart provided by Montanan indicates that both of these anchorages are open. Bahia
San Gabriel is closed because it is a major Frigate bird nesting site. The anchorage was closed after publication of the 2nd edition of the Blue Latitude guide.
The island(s) are a very beautiful place - enjoy yourself.