Gerry had only been missing for a few minutes longer than normal - and they all noticed and wondered what was keeping him (he was talking to Jez). The idea that he could have disappeared again so shortly after his return for long enough to dispose of the dead body of a child and no-one noticed his prolonged absence is a non-starter IMO.
DW believed both Gerry and Matt weren't at the table when she arrived at 9.
'- That night she judges to have arrived at the restaurant close to 21:00, in the company of the PAYNE couple.
- That, at that time, the whole group were at the restaurant. The witness did not recall, but thinks that perhaps Gerald and MATT had not been in the restaurant along with the other members of the group.'
Gerry's 9.05pm check makes no sense if Matt has just listened at the window ( remember Gerry only intended to listen at the bedroom door). Wilkins gave a timeframe for his chat between 8.45 and 9.15. Matt's visit to 5a at 9.30 is all over the place.
9pm Gerry checks on children. Everything is fine. Chats to Wilkins on the way back to the tapas.
9.30pm. Gerry checks again, finds Madeleine missing from her bed.
IMO