I'm another one that the BBC test puts as elite, probably because of factors like socialising with a wide range of people because of the sports clubs I'm part of and also due to my significant assets by way of a modest mortgage free house and a public sector pension.
Meanwhile, back in the real world, I think for a lot of people, you can't objectively say because a lot of the criteria are so subjective, and are often based on the incorrect stereotype that the WC aren't interested in their DCs education or 'worthy' leisure activities like visiting country parks and NT sites. How many times do people say that 'these places are full of the middle classes' when in reality, they've made this assessment based on nothing more than the fact that the other families didn't get out of a white Range Rover, wearing track suits and yelling at their DC, as they know nothing at all about them.
None of the MNs who say they're middle class would meet me and decide I'm 'one of them', but I have multiple professional qualifications, a first in a STEM subject, for hobbies I read, go hiking, visit NT sites etc, but none of that changes the fact that all my older male relatives were miners, the women were SAHMs, cleaners, barmaids etc, I have a regional accent, but we went to the library, country parks etc as children, mostly because that sort of thing was free or very cheap.