Such use of affectionate terms of words like 'mate' is considered to be quite acceptable in not so formal situations in the North of England though and even some areas of the South I guess.

You may be right in that, and I heard it quite often when visiting the UK. But I don't care, and we are not somewhere in North England here and can't make their norms of usage mandatory to the rest of the world. When will these sheepkeepers understand that we are different from them and like to be?

Well, as a real Northerner myself... (I'm actually not Irish!), I would not say that we always try to force that upon other people when we are outside of the U.K.

Also, may I please ask that you do not look down upon the entirety of the North of England, we actually have a few nice, civilised and developed cities, not just shithole mining towns full of illiterate unemployed people. Some of us can even speak very standard English when required to as well, lol.

Personally speaking, I don't do force the habit upon other people because I am aware that in other cultures, referring to somebody as a friend is not something that should be taken lightly. What initially shocked me about moving abroad is that when somebody from another culture refers to you as a friend, you can tell from their tone of voice and choice of words, that it is often a heartfelt gesture and that they truly mean it. However, my initial ignorance of this meant that I would have incorrectly believed an Arab friend of mine to have been trying to flirt with me, had I not already known him to be a bit of a ladies man.

My choice to abandon old native habits has meant that over time, native speakers can find me a little bit too formal (especially the stereotypical types of Australians), if I politely address them as 'sir' or 'madame', but at least they are given that opportunity to make that all important invitation to you to address them on more casual and friendly terms.

I received quite a shock on my first trip back home, reverse cultural shock you may call it. I felt rather confused when I found that a rude, completely disinterested sales assistant addressed me as 'mate' during a little argument about something. Similar things happened a few years ago too, when some coked-up idiot tried starting a fight with me in a bar, just because I accidentally bumped into him and he also addressed me as 'mate'. Just like you, I do not appreciate anybody calling me a 'mate' if they are not on friendly terms with me, although when I go home I make allowances for it.

It is interesting that other languages still preserve the concept of a formal and casual word for 'you', whether that be tu/vous, sie/du etc, according to one's familiarity or level of respect held for that person. The English language has lost that to a great extent.