When did Eden Vale yoghurt first come onto the market (UK)?

In "A Study of the Evolution of Concentration in the Irish Food Industry 1968-1973" (pg. 37), by the Commission of the European Communities, Eden Vale (a subsidiary of Express Dairies) is cited as the first producer of yoghurt in Ireland. The report also states that 20 years ago (circa1948) yoghurt was not consumed to any great extent in Ireland.

After WWII Express Dairies was involved in the development of the first supermarkets in the UK. The first supermarket established being the Premier Supermarket in South London. Express Dairies would of course stock their stores with their own products one of which was yoghurt. Therefore, Eden Vale yoghurt mostly likely was first marketed in the UK in the 1950s. By 1966, the demand for yoghurt had grown in the UK and Eden Vale yoghurt was being promoted in full page magazine advertisements.

https://en.wikipedia.org/wiki/Express_Dairies
https://picclick.co.uk/Eden-Vale-yogurt-1966-magazine-advert-310345802414.html