icn530 UK map updates

I bought the navman icn530 in october, never having used a gps system before. i don't use it that often but am frustrated to sometimes be told to take a certain direction at a roundabout only to discover that the roundabout no longer exists having been changed into a junction system/motorway entrance. I have read on the navman site that new maps must be purchased, which i think is more than a bit cheeky when the system is but a few months old, but I cannot seem to find UK-only maps which is all that I need. Since this is all new to me I am probably missing something so i'd appreciate some help.