Many thanks George, have received your scans, excellent!
I've hastily stitched some images together and attached a reduced size/quality version (to fit forum) as it shows some of the radios as well as the television. A quick surf around the net so far shows the featured radios were all released in 1937 and 1938 (for example refer
the Radiomuseum). Also I need to check but I'm sure I read somewhere (the Radio! Radio! book??) that press button tuning was the big feature of 1938.
If I were a gambling man, I'd go for around September 1938 since the brochure mentions 1939 models, often the case around Radiolympia time.
TTFN,
Jon