I think if you say you heard yourself say something, think it's middle class and are embarrassed by what you said, or think you're now a middle class 'wanker' or even hate yourself for it, then you are quite clearly not middle class.
Middle class people would not even register the fact they had said it.
It shows instead that you aspire to be or think you are middle class and so when you say one of these things, it gives you a nice-albeit false-feeling of having joined the class you aspire to be part of.
There is nothing wrong with that at all.
However, to hate yourself because you 'found' yourself texting your husband that you had ordered two Le Creuset spoon rests-as a PP described-is rather sad. It's sad for two reasons. Firstly, because this non event would not have even registered on a middle class person's radar-certainly not enough to text about it-and secondly, because it clearly is a big thing to the PP-she's pleased but hates herself for her aspiration.
There is nothing wrong with aspiring to be part of what you think is a better class-mothing at all. You don't have to hate or judge yourself, or call yourself a wanker for this innocent ambition.
The only thing to be careful about is the fact that if you do mention brioche, horses, spoon rests, ski instructors, avocados or whatever you judge is a marker, is the fact that you are flagging the fact that you're faking it to make it to those who are not faking it.
These things are normal and are really not worthy of comment. We get it, you want to join the middle class. There is no need to use this perfectly reasonable want as a stick to beat yourself with. So much self loathing.
One day, if you "succeed", you won't even hear yourself saying these things, let alone hate yourself for it.