Looking for information/images re. the Martlet and it's deployable floats on ditching

Hi, thanks for reading my post, I wonder if anyone can help?

I was recently reading Eric ‘Winkle’ Brown’s book “Wings on my sleeve” and the part he discusses about his time in the Martlet and aboard HMS Audacity. A couple of questions arise from this so here goes.

Does anyone know which version of the Martlet he flew while protecting the convoys? I ask because the F4-F3 had static Wings and the F4-F4 had Gull Wings.? The Audacity didn’t have a below decks position for the aircraft and he writes that the aircraft sat and were maintained n the deck. Does anyone know which model?

The second and more intriguing question (for me) is what he describes as deployable floatation devices that were activated when the aircraft ditched. I cannot find a reference for this device/system , what it was called, how it worked (auto/manual) me where it deployed from on the aircraft (Wings/fuselage?) and if it was manually deployed where it was activated in the cockpit.

Sorry for lots of questions but I had not heard of this until I read his book and tracking down information has been a challenge to say the least!

Thanks for any help, cheers, MP