thats about it, just like to add them preformed arch kits from wickes 16.99, do the job luverly..
rip out door liner (easiest way is cut through the middle first then just bar em out...
stick the arch kit in...btw if its double sided youll need 2 pairs of quadrants...you get two quads in a set..
mix up some hardwall or whatever...bond out the arches, youll see when you get em, easy enough but as gary says, spend a bit of time gettin em bang on...
stick some thincote angle underneath em, lined up bang on with the bottom of the arch...bond the reveal where the liner was...
good way to fix em off is get a hammer cordless, 6mm masonary bit, shove in a red plug and bang in a 40mm galvo clout..assuming its rendered..
if you set em up right theyll look fantastic when skimmed...
bloke of your talents...peice of cake...
tip: if you ever get to do an arch thats wider than a door e.g. 1200 say...just snip the square section of eml off and use more arch kits, you can make em whatever radius you want then...just done a couple, wish id taken a pic now...