Do I and my wife consider ourselves millionaires ?
You are nearly 1 millionaire between you. You may have deferred tax liabilities which you haven't considered. You use 40% of your wealth to live in, so not quiet the same type of free wealth as cash. Your pension assets are also tied up by the pension rules so not totally yours to do with as you like.
If we would be classified as millionaires then I imagine there are lots of us around.
There are lots like you around, but owning a €400k home with (almost) no mortgage is not that common.