Just had to replace the light outside the door as the old one had melted a bit at the back (60W GLS and left on all night by mistake - so much for rating - then heavy rain=bang!
Got a new one from Argos that included an 11W CFL, ES and, amazingly, Megaman (sponsored by E-on). The lampholder is supposed to be at the bottom and the rating is for 11W CFL max(!), but I had to mount the light horizontally as the cable through the wall is a fixed position and so the housing fouled the overhanging lintel.
Seems to me that there shouldn't be a problem with heat with either the lampholder or the glass dome - is that reasonable? Also, I can't see that the IP44 rating is diminished, other than there being only a screw at each end. It's on the weather wall, so gets a bit damp at times.