Two varieties of the 1914 penny were characterised by John Dean. Both were struck with the London obverse and Birmingham reverse and they differ in the orientation of the 4 in the date. The type with the 4 leaning left is quite scarce.
London Mint mark
The 4 in the date is fairly upright.
The 4 in the date leans noticeably to the left.
The dates on the specimens shown above are shown here at 3x magnification and the
difference between them can be seen quite clearly. Note that the 4 in the first
example is aligned almost directly with a rim denticle wheres in the second example
the 4 is aligned with a gap. Also, the first 4 is closer to the 1 than the second
4 (1.1mm vs 1.2mm)|