Could a UK size 10 have a length of 12 inches and width of 41/2 in? Or is this more likely a US10? Please advise...
you have to take those measurements with a grain of salt, first , the person might have measured not approximately enough ...as all size 9,9.5,10, etc can measure 12 inches in length generally.
second, he may be measuring the sole, which, if it is length, that is fine because although the welt extends past the toe's upper leather a bit, it sometimes is compensated by the heel as the heel upper sometimes extends past the stacked heel.
but the width , more than likely the sole/welt extends past the upper leather by sometimes as much as a third of an inch.
if he was measuring the sole: that 12 inches and 4 1/2 inches sound more like a 9 WIDE in US.
all my 10 D shoes on the sole measure around 12 1/4 inches in length and 4 1/2 inches in width but 4 -4 1/4 inches in width if measuring the uppers.
thus, that measurements sounds more close to a 10 D than a 10 E UK as that is a 10.5-11 D US.
however, even as a 10D it is unlikely