Help With ID On These UK Stamps

Just looking for some help in IDing these stamps. I know they started in 1913 and reprinted in 1915 1918 and 1934 (hope I got those dates right if not refer to signature)

The easiest one to identify here is the last stamp, SG 451.

THis shows both diagonal and horizontal lines around the King's head ans so must come from the 1934 set.

Nortener0 - these are some really iconic stamps ! As already pointed out, the last stamp is from the latest issue 1934. The first 3 stamps could be from 3 different printers, Waterlow (1913), De La Rue (1915) or Bradbury Wilkinson (1918). All these issues have identical wmk¨s and perfs, so other identifiers are needed. The 2 first issues measures 22mm vertically - the 3rd issue measure 22,75 or more vertically. Also dates from postmarks could be useful. Your first stamp is cancelled Jan 1915, which make me think its probably a Waterlow.
Your 2nd stamp seems to me to have a dot of color above the frame dead center, partly covered in ink from the cancelleation. If so, itæs the 3rd issue (1918) which suits well with the cancellation 1921.

Thanks nigeic and Blaamand for the info. The frist stamp does measure 22mm and with the Jan 15 cancel I agree with the Waterlow id. Stamp 2 and 3 measure 22.75mm but they look to be the first design with no diagonal lines in the shading around the king. Would that not make them they 1915 stamps. Stampworld has the 1913 and 1915 has first design and 1918 and 1934 as new designs

The stamps measuring 22.75mm in height will be from the 1918-19 issue printed by Bradbury Wilkinson.

The 1918-19 issue was created using new curved plates but it is still essentially the same design as the 1913 and 1915 issues.

Most of the 1915 stamps were printed from the same plates as the 1913 issue but, while there are some differences in gum and colour, the main test is in the size of the perforation holes.

The Bradbury Wilkinson stamps have smaller perforation holes than the first two issues. They also have a larger perforation tooth at the top of each vertical side.