I deleted the skin.ini file and then the helmet showed up ingame.
I don't know if that's the best solution but it worked.
Anyways, here are some things I'd like to mention:
1. You included the pink Hypersoft tyre although the softest tyre for Melbourne was the purple Ultrasoft, maybe you can switch them out in the next update!
2. I don't know what happened but it looks like the texture on the Halo is very low-res, it also looks very strange if you look at it from the side/front, some parts have a carbon pattern while others don't, it doesn't look uniform overall, it should have a nice dark black colour.
I don't know if it's possible to place a logo on the Halo but there's that Gandys flip flop logo on the Halo as well.
https://i.imgur.com/jkd5EIN.jpg
3. If you use the look-from-behind cam you can see that the Petrobras logo on the left and right aren't symmetrical. Also in Australia they used the BR Petrobras logo.
If you look from the side the Petrobras logo isn't straight but is pointing upwards towards the rear, maybe you can straighten it a bit?
https://www.racefans.net/2018/03/24...-prix-qualifying-day-melbourne-australia-219/
4. There are Logitech logos on the top of the headrest on both sides.
https://i.imgur.com/jkd5EIN.jpg
5. There are @McLarenF1 logos on the front part of the headrest, basically next to the steering wheel.
https://www.racefans.net/wp-content/uploads/2018/03/racefansdotnet-XPB_924266_HiRes.jpg
6. There's something wrong with the @McLarenF1 logos next to the mirrors on the side of the chassis.
They are black as they supposed to be but it looks like they are surrounded by a white/bright orange stripe ingame.
7. For Australia the Renault and Dell Technologies logos have been placed differently. The Dell logo has been moved forward towards the center of the car and the Renault logo has been moved downwards for better visibility, now it's basically next to where the rear suspension disappears in the bodywork.
https://www.racefans.net/2018/03/24...-prix-qualifying-day-melbourne-australia-219/
https://cs9.pikabu.ru/post_img/big/2018/03/07/6/1520415908224188655.jpg
https://i.imgur.com/7l7ZPfL.jpg
8. On the base version there was a Hilton logo on the bottom of the rearwing endplate.
For Australia they painted the bottom part of the rearwing endplate black and moved the Hilton logo to the frontwing (as you already did).
https://www.racefans.net/2018/03/24...-prix-qualifying-day-melbourne-australia-219/
https://cs9.pikabu.ru/post_img/big/2018/03/07/6/1520415908224188655.jpg
9. There's a FIA Action for Road Safety logo behind the helmet, not sure if it can be placed there though.
https://i.imgur.com/jkd5EIN.jpg
https://www.racefans.net/wp-content/uploads/2018/03/racefansdotnet-XPB_924266_HiRes.jpg
10. For Australia they've put the driver names next to the helmets/below the air intake.
https://www.racefans.net/2018/03/24...-prix-qualifying-day-melbourne-australia-219/
https://www.racefans.net/2018/03/24...-prix-qualifying-day-melbourne-australia-202/
That's basically everything I've noticed while testing the skin, nothing big but only a couple of small detail changes. If you rework these things we will have a perfect skin in the end!