Im very new to the whole sat nav thing and ive just got a garmin c320. I was told it gave you the option to search via postcode (5 digit) but my unit does not allow me to do this....i have seen a friend c310 and it gave the option search by "spell city/post code" but mine only says "spell city" can anyone help me with this as im going to send it back if it doesn't do what i was told