I've created 2 maps using a single address field, one with addresses formatted "1 Sample Road Postcode" and one with just postcode. They both create maps where the icons show up offset from the actual street in the majority of cases. The same data geocodes accurately on Google Fusion.
Any suggestions on how to improve the accuracy?
Your best bet is to take a look at this site http://compare.innovationgeo.com/ and let us know if one of the 3 geocoding services is providing more accurate results than the others. If this is the case, we can update your map to use that specific geocoder via the back end.
I have found the same issue and according to a couple of samples I have found that Google is the better geocode. My map seems to be using Yahoo according to my comparison with what MapAList and Geocode Compare is showing. How do I select the geocode service for my maps?