Hi! I have managed to crack the screen of my 'unbreakable' AGM X3.

I have received the replacement screen from the phone supplier here in Australia, Rugged Phones Australia. However no one is willing to do the repair as they do not know the phone. 

Judging by the replacement screen, which is the entire side housing including digitizer and screen, it seems its a matter of heating the rear panel to remove the rear cover to allow access to screws holding the internals to the housing. 

Can anyone here please recommend a suitable heat gun to purchase plus what other tools I should acquire and method for undertaking this repair please?

Thanks in advance,

Coxy