C and J Motors Ltd in Parkgate
http://www.uccc.co.uk/garage-services/south-yorkshire/rotherham/c-.and.-j-motors-ltd
Used them for years now on the missus's car.
Roddisons Motorsport on Shepcote Lane, Sheffield.
http://www.mx5-racing.co.uk/
This is who I take my MX5 to.
Both very trustworthy in my opinion.