If like me, you have the Amundsen Satnav and think that you cannot search for a postcode, you can. Go to the Navigation screen and select a new destination. When you go to input the Town, if you look in the bottom left hand corner of the screen, you will see a box "Ptcd". Touch this and it opens up the Postcode search function. Why don't they put this in the instruction book?.

I know - it's a serious omission, took me a while to find it on the Columbus lol

I was wondering where that was - I am sure you could just enter a postcode in the Town input on the RNS-510 Columbus, but it is a while since I last had one!