A guess might be Mick Stephenson ... you need John Melchek or someone cleverer than me ... Many years ago I proposed a register of Ex Workers (with their permission) but it got pooh pooh'ed on here ... on the grounds of privacy by your Editor of Sprint.
One of my door panels is signed by a Steve. It's also signed by previous owner Colin Sellers who I've not tracked down yet. Quite keen to know why he had to bring the car back to life in 1990??
The face is that of Gary Numan, painted by Brent (Jagged Halo) who was a great fan of his. Brent is a great guy, he painted the face on an A4 sheet of paper for me after the factory closed - still on the wall in my 'office' at home.