Median post-tax household income in the UK is £30k. So, £25k each is roughly £20k post-tax, so you're looking at the top 30% of households.

Admittedly this includes households including people who are "retired" but I think that's reasonable as plenty of people have to keep working even though they're receiving a pension.

https://www.ons.gov.uk/peoplepopulationandcommunity/personal...