All I know is that I bought a 07 a few month ago, didn't have a head unit. I forked out and got one which was a Rt3evo fitted with a hard drive.
Before that someone checked out on this site that rt4 was originally fitted in car.
Unit I'm running has 7.3 firmware
The RT3 maps work off a CD that needs to be inserted in the player at all times. This unit would normally come with a CD multichanger in the car somewhere..
The RT4 has an internal memory drive that have the maps loaded on to it.
So the upshot is, if it needs to run the mapping CD while navigating then it's an RT3.
thanks for your help guys, it does have the menu icons in a circle, I purchased the software upgrade CD ver 8.31 from Peugeot it cost £7 but when I put the cd in it would not read the disc and would not eject the cd so I had the remove the unit and strip it down to remove the cd, tried this a few times still got the same result, any ideas what to do next please