Anniversary edition of Bunnikin's Picnic Party.
In the early 80s this book was still in print (over 40 years of continuous service!). The matt finish of the covers was replaced with hard-wearing laminate until it was finally taken out of print.
But in 2000, to commemorate the 60th anniversary of Ladybird, 4 favourite old titles were re-issued with matt boards - as you can see here.