I think that by 8pm the Carpenters would have finished their evening meal, and this provided an opportunity for both of them to leave the tapas restaurant temporarily, so that Christine Carpenter remained on the pavement keeping a conspicuous eye on the McCann premises whilst Stephen Carpenter returned to their own apartment to check on their own two children. In the interim period, the tapas nine group and the McCanns had filed into the tapas restaurant (between 8.15pm and 8.45pm). This fits in with..
Stephen Carpenter saying that all the tapas nine group were already there when they went back to the tapas restaurant, but in fact the McCanns themselves, and one or two others in their group did not arrive at the dinner table until 8.30pm, and afterwards. For example, I think that Jane Tanner or Russell O'Brien, arrived much later on because their child Ella had been taken ill, and they took it in turns to stay back in the apartment with the child, swapping over during the course of the evening!
What we do know is that neither Jane Tanner, Russell O'Brien, Gerry McCann, or Mathew Oldfield saw the woman in the plum purple dress stood in the street between 8pm and 8.30pm, the only people who took note of this woman was Jenny Murat (8pm) and Jez Wilkins (8.15pm to 8.30pm)...
I am satisfied as I can be that the woman in the plum purple dress was none other than Christine Elizabeth Carpenter, she was alone which freed up Stephen Carpenter to take care of other business! This other business was perhaps to return to their own apartment which was situated nearby, next to Jenny Murat's premises, to check on their own two children! It may well be, that the Carpenter couple kept in contact with eachother throughout this time by mobile telephone calls!
I think everything fits into place, whereby at sometime after 8.30pm with the departure of the McCanns from apartment 5A via the patio door on the poolside of the building, and their arrival at the dinner table by 8.30pm, or thereabouts, that this information was relayed from the woman in the plum purple outfit on foot out in the street, or perhaps on her way back to their table at the tapas restaurant, so that she was met by Stephen Carpenter so that they sat back at their table after what they believed was the full Entourage of the tapas nine already at their pre-booked dinner table!