From 1937 to 1947 there was a wide range of issues made for the ½d (SG.75b/bd, note Part I catalogue gives the dates as 1937/40). They would require careful study to collect properly, though there are ways to identify them, especially through their shades and marginal markings. I must admit I have never looked at these half pennies too closely, but there are a few collectors out there who can’t get enough of them!
There are additional issues of a number of the other low values throughout 1941/51 period. The 1½d Mining stamp was issued in a reduced format (SG.87) in 1941, then the size was further reduced in 1948 (SG.124) into a “bantam” format with perforations and rouletting used. The 2d was also issued in a reduced format in 1950 (SG.134), however, before that issue, we find the 1945-8 issues (SG.107, 107a, 107b) that had a redrawn vignette compared to the previous issues (SG.58, 58a). If you are a specialist collector of South Africa then there are NINE different issues between March 1945 and May 1948 to hunt down! Most of us will satisfy ourselves with what we find listed in the Part I catalogue, but it certainly gives an insight into how many 2d stamps must have been used to warrant so many different issues of this value.
Don’t forget the redrawn 1d issued in 1951 (SG.135) which is a common stamp both mint and used. Contrast this with the 1948 ½d (SG.126), the so called “Economy” printing made to use up a stock of old paper. This stamp is incredibly common in mint condition, but very hard to find used and also tricky to find used genuinely on the post, i.e. not for philatelic purposes.
The 4½d, 1s3d & 1s6d definitives issued on 1st October 1953 (SG.146/8) are worth seeking out used on first day cover as these are quite hard to find.