History of Wigan   (Help with ancient and recent history.)

Hello
Can anyone help with memories, or even facts!, about The Park Show. Hoping to include some information in an article for Past Forward.
Does anyone have a relative who worked on it? How long was it on? Was it free to enter? Was there a big celebrity opening? I remember the Heinz tent and the free tasters of tomato soup (or at least I think I remember that) and the marquees where the flower arranging etc were on show.
Any information gratefully received. Many thanks.