ok guys, its done .. and with success !
I downloaded the .iso file from GpsUnderground link on this page ...
http://gpsunderground.com/forum/peugeot ... nside.html , I can confirm that this file 140507_1353.ISO is product number 9691737180 (cd #8784) and is suitable to upgrade a RT6 to software version 2.80, in my case I went from RNEG 2.75.C.5 to RNEG 2.80.E.2 the same as Tianorth (see his screenshots earlier in this thread, but check your car/sat nav model number and current software version before proceeding ! )
I had already updated my UK mapping to the latest version 2014.1 using downloads from GpsUnderground using the MEGA link in this page ..
http://gpsunderground.com/forum/peugeot ... nside.html and also the Speed Camera database (Alert Zones and Risk Areas) via the link on the same page, these I installed (seperately) via a 4Gb USB stick that I saved the files to, be sure to first run RT6_Mirascript v01.03 found on this page ..
http://mira308sw.altervista.org/en/ (you only need to use the RT6_SETTING.CMD to alter the setting of DRM from 1 to 0, this is to get around the Activation request issue .. ie: you will not now be asked for it anymore !) , I suggest you read up on using Mirascript to familiarise yourself on its use before attempting).
As far as updating to v2.80, burn the .ISO file to a cd (I used Imgburn which is available free online ..
http://www.imgburn.com/ ), run your car engine and do not turn it off until the process is finished (approx 40 minutes), turn on the RT6 radio/sat nav, select radio, press mode switch until there is no sat nav info on the display then power off the radio (via the 'power' button, now insert the disc.
It will first 'error check' the cd then ask if you want to update, answer Yes ... as I said it takes in total just under 40 minutes, will initially reboot, load in several small files then one very large one, followed by more small files then another very large file, a final reboot and then it is done, at this stage it will have recognised your cd again and will do another error check, when done .. this time answer No to the update and eject the disc .. Job done !
I can confirm that I now have full 7 digit UK postcode ability !!