Copies of the original Wireless World articles from 1947 and 1949 can be found herehttp://www.dc-daylight.ltd.uk/Valve-Audio-Interest/Articles-for-the-Web/Articles-for-the-Web.html
There's a rather odd American critique of the circuit here http://www.stan-white.com/a_doc_Williamson.htm
Obvious errors in the critique (aside from spelling) include
* suggestion that the amplifier hadn't actually been built - the 1949 article makes several suggestions for improvements based on experience of use.
* the amplifier relied on a Partridge transformer - Williamson gave construction details for the transformer in the article.
* that it is possible to use large (100s of microfarads) smoothing capacitors with a valve rectifier - it certainly wasn't in 1947, and makes little sense even today.
The writer also attributes ideas to Williamson that are patently untrue - Williamson didn't break with convention in using all triodes. His amplifier was based on the Wireless World quality amplifier, an all triode design from 1934.