Dave Clarke fife,
A perfect example of a confusing presentation. Your original post had all the hallmarks of being your own work leading to the response from Northbeach.
I have long thought that the use of the phrase, "....descend to....." and similar is confusing and have tried to avoid it in my own RT use preferring something like, "Leaving 5,000 on descent 2,500" and similar.
I remember hearing an audio tape of the Tiger 66 during my ATPL theory course and thinking the same as Northbeach along the lines of, "what crew could possibly think a non-precision approach starts at 400'". The only possibility I could think of was that they were at the end of a long flight and fatigue had set in.
As to the gear warnings, I don't think it would matter how many syllables it was. The problem comes when the attention is firmly fixed on the task in hand and the mind starts excluding other senses as a distraction. I suspect this crew were concentrating so hard on the problem of the flaps and the approach that the gear warning was excluded from their loop. Perhaps if a visual stimulus cannot be provided an alternate aural warning is required to break through the concentration set of the pilots, something along the lines of "Hey effwit, lower the effing gear" in a very loud voice.
In Australia the tower, both military and civil, is required to transmit "Check gear" to landing military aircraft. Perhaps it should be required where an aircraft is making a non-normal approach.