I've just been talking to someone (via email) about when CE marks were introduced and I thought you would be interested to hear my deductions.
I searched the internet and found this website
http://www.ul.com/international/europe.html
This shows it was law from 1985.
Now I just received some old shop stock of cricketers and these have the round CE stickers, they were in production from 1981 until 1986 so it would make sense that 1985 was around the right time because we know there were no CE marks in the cricket molds, yet they obviously had to start using the stickers when these were still in production because I have them with the stickers.
So 1985 sounds about right to me but then I guess it depends on when they started actually putting the mark in the feet.