As labeled on the front of their wrappers, Both the Warwick and Dunlop Warwick Fifty-Fifty balls have a mixed dimple and lattice pattern (also called a round and square dimple mix) on their covers.  Both were made by Dunlop, but the one with the black label that includes the British design registration number (No. 716,953) appears to be older.

The Warwick 50/50 was introduced in 1930, but remained on the market for a number of years. Golfers could also buy Warwick balls with either a traditional dimple or lattice pattern. 

Because both of these balls are wrapped, I have included a separate image of a 50/50 ball to show the pattern.  The unwrapped ball is not part of this lot.