Apart from one family outing in June they had never before visited that area and did not visit it after this cluster on 19th, 26th, 27th, 28th July, 1st, 2nd August.
It is interesting that neither Gerry's blog nor Kate's diary/book nor media reports cover these visits that all happened in the late afternoon/early evening except for the 1st August when they returned to Praia da Luz after 22:00. We can safely say that they were not followed by any reporters on these trips which renders their argument useless that they were constantly watched and never had a chance to dispose of a body unnoticed.
A burial somewhere in that area could remain undetected for years but the ground in Portugal in the summer heat will make digging very tiresome if not impossible. So what else is there in that region? We have a long stretch of coastline with innumerous little bays and caves. There is an impressive monolith right in the center of the triangle. There is a cemetery outside Vila do Bispo and some lonely chapels as well.