Replacement headlight lens

I have split other headlights but not these. In the same boat as regards making a mess of these
 
You have to bake the headlight in the oven or otherwise apply heat with a heat-gun until the glue is soft enough to split the unit.
The danger is that both the headlight and lens are plastic, so if you overdo it you are in trouble!
 
Yeah it was the thought of sticking in the oven that put me off!

Those ones claiming an easy fit (and no replacement glue) I have my doubts about!