There was me thinking I wasn't that badly off, despite feeling perpetually skint, but apparently "with a household after tax, after housing cost income of £350 per week, you have a higher after housing cost income than around 22% of the population" so am firmly in the bottom 25% of households. Yes, the tool is a couple of years old but I found it earlier and it's probably still relevant as a comparison tool.
https://ifs.org.uk/tools_and_resources/where_do_you_fit_in
I wonder what the Mumsnet average is?!