Where do I stick a sat nav in my Peugeot 307

up the rear end

in a small hole??

in ya girl,s gob

Here is a photo with one in the dashboard.:
http://thepeugeotshop.co.uk/product/Clarion_NVS613_Satellite_Navigation_Unit_For_Vehicles_Without_CD_Multiplay_VAR743

Here is a photo on some Sat Nav is that come with a base, to mount above the dash:
http://speedculture.co.uk/osc/satellitenavigationsystems-c-3988.html

Here is an article that says the new QUICKSILVER 307 is comes with Sat Nav already installed at the factory: Have a look at the dashboard of one u see on the street.
http://indiacar.com/xnewdet.asp?id=n8087

Normally, for peg 206 and also 307 there are some multifunction displays: type: A,B,C
the C type includes a nav system too.

Window, get a sticky one and put it to one side of the steering wheel. or on the dashboard, it mainly depends on what type of sat nav you have purchased.