"...If you are asked to pay in full at the time you place the order ...then you are not in any way "pre-ordering" the item ...you are ordering it, period. There is an implication that the item is in stock and available for dispatch or collection.


"...the form said I was pre-ordering the bloody thing, yet I had to pay a deposit amounting to half the price of the still-gobbling beast.


"pay in full" is not in any way equivalent to "deposit amounting to half the price" ...

I would concur that "pre-order" is indeed a neologism, one which would possibly have caused raised eyebrows on the part of Shakespeare and Dickens, but I would contend that in this modern world, it is a valid and acceptable term for what has become standard commercial practice.