Hi Nicko, the seat in your picture looks like a mk4, the Mk4P is fitted to the Jet Provost which would match the fact it has ‘port seat’ labelled on the head box.  However, looking at my copy of AP129 the following aircraft were fitted with the Mk. 2 seat:

Wyvern Mk. 2B 

Sea Hawk Mk. 2D

Meteor Mk. 2E

Venom Mk. 2F

Swift Mk. 2G

Hunter Mk. 2H

Javelin (aircraft mks 1-6) Mk. 2J.

The Swift, Hunter and Javelins were also later fitted with variations of the Mk. 3 seat too.

Regards,

Martyn

GYD