Finally they arrived from USA after a week.
The front clear reflector is sealed with superglue or some sort of adhesive to the back casing. Not happy bunny! I was hoping it was silicone so that I can bake them and separate them so implant the LED PCB. After some Google'ing, managed to find some info.
1.) Soak in hot soapy water, hope the water will slowly dissolved the superglue a little bit and slowly split them apart.
2.) Soak in boiling water, that should also do the above and soften the superglue ready to be split.
3.) Put them in freeze and freeze them for few days. Apparently the cold will shrink the superglue hence they will start cracking and makes is easy to split.
4.) As above but freeze with water.
5.) If all the above fails, I can start using hobby knife and try to cut it or as a last resort, cut the back casing to size so that I can fit the PCB in and seal it back with silicone.
Sounds like a mission! Hopefully it will split, which will make it easier to seal back.
Anyone done this before? Any tips or best practice sharing?