The Sea Vixen seat is similar in overall shape, although the parachute pack and harness are rather different. What appears to be 'silver grey' harness straps in Geo's pic are in fact a light golden brown, like the straps lower down. They were made from an artificial fibre webbing, incorporating 'Rayon', which has a shiny surface, not unlike seat belts in today's cars. What you are seeing is part light reflection from the camera flash, and part 'anomolous reflection', which is the inability of certain colours to record absolutely correctly photographically under certain lighting conditions.
The parachute pack is the dark green 'horse shoe' shaped container on the upper part of the seat, with the 'V' shaped straps coming out of it. These are the parachute lift webs (risers), and are an 'off-white' colour, with a red 'dashed' stitch running up the centre of each strap (this was a safety indicator, and also added strength, but allowed a certain amount of 'stretch' without the strap breaking - lift webs and harness, under a heavy opening, can stretch up to around 150% in a fraction of a second, then return to normal). The parachute pack itself is made from a later material, a type of nylon 'canvas', which was Olive green in colour (although it looks grey green here), and this more resilient material replaced the earlier natural-fibre canvas, which was brown, not yellow.
The colour of the earlier material, as used on the Sea Venom, was the same as that seen on the 'wedge pad', which is the brown, rectangular 'patch' immediately below the yellow and black firing handle.
The lower straps, coloured blue, are correct for that period, and are the same colour code as 'anti-g' straps, and leg and arm restraints, being an indicator that they are a different set of straps from those of the parachute assembly, and are part of the seat. These are actually the seat harness itself, which, although also connected to the parachute harness, are the main seat restraint, and are also connected to an inertia reel, to allow forward movement - this inertia reel immediately locks on operation of the firing handle.
Behind the harness is the back-rest cushion with lumber support, and again, this would originally have been the brown colour mentioned, on the Sea Venom. In the seat pan are the seat cushion and, below that, either a dinghy pack or PSP (the PSP came later, being a combined dinghy and survival pack, in a yellow container).
Again, on the Sea Venom, the seat cushion could have been the brown canvas or, as shown, the darker brown 'leatherette' material. The dinghy/PSP, may have been yellow, although this colour was a later addition with the introduction of a rigid container, or may have been as shown.
Sorry for the long reply, but the changes in materials over the years affected the overall look of various ejection seats.
Hope this helps.
Evan, leave it with me, and I'll see what I can find.