1980 for me...I first saw on the back of the Meccano 20 backs whilst on holliday on the French island of Corsica. Me & my bother went mental trying to find him (and drove my parents nuts) but as it turned out there were hardly any figures to be found anyway - just Leia, Ben & C-3PO, all of which we bought as the packaging was so different. The 12" range were much more readily available and for around a tenner - much cheaper than back home where Chewie was a staggering £25 in our local independent toy shop. I guess we were used to seeing toys that were different or unavailable from the catalogues (notably Dewback and the white prototype spaceships) so perhaps concluded finding a carded Blue Snag was a lost cause!
Also recall the Motta (?) ice cream from this holiday (the only time we went abroad) and never being able to get the free collector cards advertised... (10 year old me unable to speak a word of French pointing repeatedly to the wrapper flash and a French cafe owner getting impatient cos I wasn't giving in!) I still have a wrapper as a memento - it may not be a carded blue snag but better then nothing.