I am totally confused.
I read the tag needs to show name of the owner AND address - by law.
Just had one engraved and the Timpson guy (expert in the field because he once had a cat rescues by the RSPCA
) told me no, address does not need to go on 
Our rescue grey is currently ID tagged as per the rescue he came from, also his microchip is still registered to the rescue, all of which I need to change tomorrow, so I'd quite like to know what exactly it is that I MUST do - obviously there's a whole other thread to be had whether his name should go on or not etc etc.
Has the law changed on 1.4. when microchipping became compulsory?!