That's incorrect. The evidence that the house was secured from the inside was dealt with by Ann Eaton's idea of banging the latch down on the kitchen window from the outside and Barlow witnessing her do it. And the lower latch by the sink was conveniently never brought into the equation.
Bamber's admission he could enter via secure windows cannot be used to explain securing windows from the outside. Because the admission does not involve him claiming to be able to do such a thing.
The ground raised at the Court of Appeal in 2001 was purely on the basis of entry via the bathroom window due to scratch marks being absent on the 7th of August. Whats going to the CCRC now is the high resolution photos of the kitchen window showing the lower latch down and that the window could not be secured from the outside (contrary to what AE and Barlow stated).
Simply entering and exiting windows is one thing, securing them from the outside is another.
Of course I agree with what you're saying on principle. They should acknowledge that Bamber's admission that he could enter and exit the house does not not amount to an admission that he could fake the appearance of the house being secured from the inside, but the authorities have demonstrated clearly that they won't give in to that reasoning.
What is involved here is the use of the compound question by lawyers.
There is an evident intention to blur the distinction between the two questions, so that they both must have the same answer. Why do you think that such scoundrels will have a change of heart at this stage and decide to do the right thing?
Paul Harrison, in Deviant, actually argues that the two questions are really just the same and criticizes Bamber and his supporters for trying to separate them. He can't really be that stupid. What he was doing, it seems, was to defend the judgement of the Court of Appeal in 2002, which gave its full support to what Justice Drake said on the matter.