It is certainly 4-4-2 as almost all teams in England were using that formation back then.
Of course the English Premier League didn't exist in the 1980s as it started in 1992, but I have assumed the question relates to the top-flight English league, so that would be Division One (the First Division) pre-1992.
One reason often cited for the poor performance of the English national football (soccer) team is that the club sides play the predictable 4-4-2 formation and this isn't effective at the international level. So often the England national team plays a variation of this, 4-3-3 for example, but as the players are not used to it this gets used as an excuse, rightly or wrongly, for their underperforming.
Wikipedia has a lot of information on this topic and you can see 4-4-2 has been popular in many countries until recently:
http://en.wikipedia.org/wiki/Formation_(association_football).
Liverpool (for one) are still using the 4-4-2 formation and dominated English football especially in then 1980s,the 1980s; here's another interesting link:
(if the URL worries you, it is about soccer, I promise!)
http://thebeaveronline.co.uk/2012/03/15/the-death-of-the-4-4-2/. (If the URL worries you, it is about soccer, I promise!)
