Czech Milatary colour change flashlight

Ive searched the site and cant see anything similar appologies if there is!

Hi guys Ive been a long time reader but joined in the hope of a little advice.
I want to mess about with my Czech Military flashlight.
The easy option I can see is a straight swap of the e10 screw in torch bulb for and led type, but I wondered if i could take out the reflecter and bulb and glue/fix in a drop in type assembly etc. The dia of the reflector is about 33mm i think the lens is glass.
The flip up coloured lenses are plastic so will prob only be able to use in short bursts if heat is an issue

There is about 35mm depth behind the lens to allow for the reflector/lamp assembly
Battery wise there is space for 2 d or how every many AA that space will hold plus more if I rip the guts out of it

Thanks guys - completly open to ideas but please keep it simple

I don't think you need to worry about heat affecting the color lens. LED heat goes out the back side into a heat sink. Doesn't seem like the kind of light that needs more than 100 lumens.
So heat sinking needs will be low
There are 35mm TIR optics only 16mm deep, room for a small heatsink as well, like on an old computer graphics card