The minima are certainly exceptional.
As far as the overall CET goes I remember reading in Philip Eden's writeup of April 2012 (which I struggle to find online now sadly ) that although that month was the coldest since 1989 there were maybe 6 or 7 colder ones in the 60s, 70s and 80s.
Which is a roundabout way of saying that the run of warm to very warm April's that dominated in the 1990s, 2000s as well as much of the 10s have seriously warped our expectations of this month.
In the 70s or 80s I daresay this month would look far more ordinary