"X" marked P-14 receiver

[Patrick Chadwick]

The difference between the 2 models is that the Mk1* has a slightly longer[few thou] left hand bolt lug,

Actually, according to Stratton, it's a full 0.10". See British Enfield Rifles vol. 4, P. 58. Fig. 3.3. Done to strengthen the lug, so definitely not a few thou!

Patrick