Trouble with a timeline is the Polish built cars are a bit confusing and the language doesnt help!!!
But its something like this... I think!
1972 126 with 600cc engine, chrome bumpers, 500 style wheels/hubs.
1976 Gets 650cc engine, chrome bumpers on low spec cars, 126 Deville
has black plastic bumpers, new wheels and hubs. Basically carries on
with special editions and the like up till end of Italian production in 1984 Now all UK cars are Polish made FSMs, bigger bumpers, new interiors
and at last a steering rack!
1987 Aircooled ends in UK and replaced by the BIS, aircooled still
sold in Eastern Europe as 126p.
1991 Bis ends production.
1995 New bodypanels for wings and doors, smoothed off look.
1998 I think... cars get catalytic convertors and emmission stuff.
2000 Last 126s made all badged happy end!! 400 in total.
Cars still in dealer network for a time, I saw one in December
2004 with no miles on for 3.5k!
Thats not exhaustive but a rough guide.