That was my reason for fitting them - setup so that you get light should you approach the bin from either front or back doors.
Interesting idea - ours still has a conventional sphincter.... Oh I see what you mean! ;-)
Pretty much the setup we have - I selected the consumer unit cupboard (to call it a pantry in our case would be over egging it a bit!) since it was an easy place to find power and was on the right wall.
My switch is in the "pantry" as such... must admit I have never found the need to switch the light off manually as yet, the PIRs work well. Might be handy at bulb changing time though.
In our case the power comes in overhead and runs down the wall in a vertical conduit before going through the wall to the power company fuse etc. Hence to avoid having to make an ugly crossover of conduits, I brought my own connection out about a foot below this and wired out to each lamp from there:-
# # PIR-------LAMP-------- # ----------LAMP--------PIR | # | | # | | # | | # | | # | | # | | # | | | | | ----O-----
Where '#' indicates the incoming feed from the overhead wire, and 'O' is the conduit 2 way junction box.
(The second PIR on the right I actually took about a foot round the corner of the house, so that it is on the back wall of the house near the back door - this was to avoid it "looking" anywhere near the boilers flue)
The conduit is pretty thick walled stuff. If in doubt you can give it a coat of paint at some point to protect it from UV light which will tend to make it brittle over prolonged exposure.
The temperature is not too much of a problem. The PVC insulation on the cable is good for at least 70 deg C. The lower limit is less important since its the flexibility that goes in the cold - and this setup won't (with luck) be moving anywhere.
It is usually simpler to get individual wires through conduit rather than complete PVC sheathed flat cable. Depends much on how many wires and how long the run of conduit is. In my case I fed a bit of gardening wire through first and pulled the cable with that. With hindsight I should have bought an electricians fish tape:-