The Website for all former pupils of the Prescot Grammar Schools
 
I've attached a file containing three photos. They're not the best quality but they're from a school summer carnival circa 1980.  The large orange furry womble suit in the first, if my memory serves correctly, contains Gill Burns....  
 
 
In the first 2, you can see the procession wending its way down Derby St. with the old careers office on the left of the photo I think.  If you squint very hard, you could probably make out the Sun Inn (AKA Swinging Tit) on the right ! 
 
 
The float in the 3rd photo is being pulled by a BICC lorry which I thought might trigger a few memories.