Apart from some of the early prototypes, yes, the Wyvern was fitted with a bang seat.
Some of my earliest childhood memories were of the racket the aircraft under test at RAF Merryfield made! Westlands had a small site there, which also housed a Welkin and Hamilcar X, I was told a little while ago. RA490, the deflected jet Nene powered Meteor, flew from there too. Later, Westlands had some contract to overhaul Sabres, which were very much noisier than the Wyverns had been.
Westlands site is now an official gypsy site.