Green/Orange circular disc over Chester, England

I was at bus stop with my mother,when I heard a strange crackling noise in the sky opposite where we were waiting. 
Coming from behind a cloud, about 20 feet above a house, was a slow moving green disc about 12 feet in diameter with a crackling orange revolving outer; like a large catherine wheel firework. it was not metallic, literally just a green colour. 
It was ascending slightly.I saw it first & pointed to it, saying "whats that". 
We both watched it for about 20 seconds, before going into thick cloud.  I looked about to see if anyone else was about, but nobody was around. 
I said to my mother "shall we ring the liverpool echo, a newspaper, & tell them what we saw. 
My mother replied "no they would not believe us. " 
A few years later, I read an article, that said if you ionise the atmosphere, you create a vacuum. 
It brought back memories of what I had seen, & was a possible explanation for the orange revolving outer part.  It might well have been ionising the atmosphere, creating a vacuum to enable propulsion?
Witness indicates that the date of the incident is approximate.  PD