The 12-14 1950-1956 exemplars of this style by this hand (checks, contracts, items in The Burton Museum etc.) that I have gathered for Pt II of my signature study only suggest to me that my SPc might be a little more like 1951-52, in which case I will move it forward a bit. Here is a 1953 contract signature:
And an Old Vic portrait by Angus McBean from 1956, after Burton's early "manager" Philip Burton left the UK, so who else would be signing since the late 40's in a single hand and style on letters, checks and contracts?