ITV have chosen to have three or four regional versions of ITV1, which is far from complete regionalisation.
BBC have so far concentrated on the four nationalities, but
will probably do better, sooner or later.
ITV do not have to cater for N Ireland or Scotland. They have their own channels namely STV and UTV. If and when Scotland vote for independence maybe the BBC ditching the Scottish services will allow more regional options for the rest of us.