I've searched around, but I can't find out why I'm unable to do a full 7 digit postcode search on my sat nav.

I have the Mk4 sat nav unit.
It's running V32 firmware.
The software version is 4-1/00.
I have a 2009-2 High Europe map DVD which says on it "5 and full 7 digit postcode input options"

But I can only input a 5 digit postcode, which is useless!

I've read a lot of posts found on different forums and it would seem that I have everything to enable full 7 digit postcode searches. But I can't.

Can anyone shine any light on this please because it's driving me mad?