Phase 3 wing mirrors

[Paul_13]

With winter coming up I want to get a few things sorted. 

1 the coolant  heater 
2 heated wing mirrors 
3 check if my rear heated screen actually works

Now having owned a 205 most of my life 
I've never had to mess around with heated wing mirrors. 

I take it on a phase 3 they're heated, but what temp do they turn on at? 

How does the glass come off?  

I wonder if halfords do replacements