If Gerry had gone in via the front door - he would have had to explain to the PJ why on earth he would decide to walk past the patio doors only a few yards away and take the much longer way round - especially if he needed the loo,
He'd already said the patio doors were unlocked - so why would he make such a ridiculous claim - for which IMO no sensible explanation exists. If the PJ officer interviewing him had picked up on that at the time - and asked Gerry why he went the long way round then IMO it would all have been cleared up there and then.
The previous confusion caused by some people describing the patio doors as the 'front door' and the door overlooking the car park as the 'back door' was mentioned by the police officer interviewing JT. Therefore it was decided to call the patio doors the 'poolside door' and the wooden door the 'roadside door' to avoid any further similar confusion.
It may be true that Gerry did say he came in by the 'front door' - but he was referring to the patio doors - but the PJ officer interviewing him didn't realise that during that first interview. (understandable IMO)
If there was anything suspicious or unusual in the reason Gerry gave for correcting his statement - then surely that reason would have been recorded in the second statement.
AIMO
I think it's perfectly clear. The key was mentioned twice on 4th; there was no key for the patio doors. The PJ questioned him on 10th about changing which door he had used and he accepted that he had changed it;
In this way, at about 21.05 the witness came to the Club, entered the room using his respective key, the door being locked,
At about 22.00 it was his wife Kate who went to check on the children. She entered the apartment by the door using the key
http://www.mccannpjfiles.co.uk/PJ/GERRY-MCCANN.htmDespite what he said in his previous statements, he states now and with certainty, that he left with KATE by the rear door which he consequently closed but did not lock given that that is only possible from the inside. Referring to the front door, while he is certain that it was closed it is unlikely that it was locked as [because] they had left by the rear door.
http://www.mccannpjfiles.co.uk/PJ/GERRY-MCCANN-10MAY.htm