M17s were sent over to the UK at the start of the second world war to help out with the shortage of rifles, they went to Home Guard Units and such like and it would have been referred to as the P17 here, a P14 in 30-06.
They were replaced as soon as possible, because of ammo supply, with .303"s. This where I think some of the confusion arises over nomenclature. The rifle was made and designated as Model (M) 17.