The large meal taken in the middle of the day was "middagsmad", or "midday food" (still is in the older generations, especially rurally, in Denmark), while "middag" is generally the larger, evening meal today (so, same deal as "dinner" in English).
In South Wales they talk about "cooked dinner" which is a roasted meat meal, usually chicken for Sunday lunch, but can be any time of the week. Presumably that harks back to families having lots of uncooked meals (through poverty).
That said I used to confuse some very northern friends by talking about dinner as my evening meal. They literally only thought of dinner as lunch and the evening meal was only called tea.
I think the roots were from when only the father of the house had a cooked evening meal, and everyone else had tea and sandwiches or similar. But that was distant past I believe.
I am not sure this is universal for Australia and may also not be the case now.
I'm fairly certain my neices and nephews (mostly teenagers now), no longer call the evening meal tea.
My understanding was that this usage referred to a meal eaten in the evening, i.e. not lunch. Your link seems to confirm that.
My grandmother used to serve tea for the evening meal when there were no guests other than her little grandson. But that's the only Danish example I personally know of. Don't know why, tea is not a bad drink for a meal.