Complete amateur trying to fix up an old helmet

Afternoon folks - UK based numpty looking for some advice please:
I've got hold of an old Fett helmet (one of the Don Post ones) that is battered and in need of a lot of TLC. I'm planning on repainting it as a general mando helmet rather than a fett specific one, but I need to fix it up a bit first

First big problem - it's out of shape. I've no idea if it's been sat on or what, but it's not wide enough from side to side. The helmet does flex, so I've got a bit of timber in wedging it back to roughly the right width, but when I remove the timber it deforms again by about an inch. Does anyone have any suggestions as to the best way to permanently reshape it back to what it should be? I was thinking maybe use a heat gun / paint stripping heat gun to soften the plastic with the bit of timber in place as a wedge, but anyone got any better ideas?

Secondly - since I'm going to be respraying it, I'd like to fill in the writing on the back (the "made in China" text etc - does anyone have any recommendations as to the best UK-available filler to use that will remain flexible once dried and won't crack and/or flake off? I'd looked at plastic car bumper filler as that advertises as "highly flexible", but not sure if it'll do the job?

Thirdly - related to number 2. I'm going to fill in the dent and smooth it off as I've decided I want the helmet to look bright, shiny & new rather than battered. Can the same filler be used to do this, or will I need something else?

Fourthly - and appreciate this is massively subjective. Any thoughts on replacing the rangefinder with something less obtrusive? I'm thinking either retain it and build in some sort of blinking LED contraption inside it, or bin it and replace with a small aerial.

Skills-wise: I'm a complete newcomer to this sort of thing, though I've been doing DIY, electronics etc for years so pretty much up for any challenge, so any and all suggestions gratefully received

Thanks

hi,
I too, am a fairly ill experienced fetter, but have somewhat of a background in static modelling, for the dent, I recommend sanding it rough and applying epoxy putty and sanding it smooth, for the helmets shape, I suggest leaving the tinder in and dunking it in a bucket of fairly hot water, let it sit for a while, as for made in china, most putties that come in small tubes should do, again sand it smooth, as for the rest, I am not too sure about, so I will restrain myself from giving ill, misguided advice.
Cheers, Ryan