I quote:
In France, Germany, The Netherlands and the United Kingdom, Peanut M&M's were known as Treets until 1990. Additionally, Toffee Treets were also available for some time. The chocolate versions were called Bonitos until the brand became M&M's. This was partly due to the market dominance of the similar candy Smarties which made competing under anything but a very high profile brand difficult, with the added risk of reducing sales of the existing Treets brand. Though Treets used the same "melt in your mouth not in your hand" slogan in the UK in the 1970s, this was transferred to Minstrels when the Treets brand was dropped.
I rest my case.....