They absolutely do, no question about it.
There's no way Grace or Violet bought their houses without an injection of cash from their parents.
Even though Grace has done well business wise (no doubt about it), to have put down £320000 (20% of her house price per the deleted video) + stamp duty (ETA this would have been at least £100k based on the sale price, even as a first time buyer. Could have been tacked onto the mortgage though, but it's generally advisable not to) + solicitors fees + paying for extensive building works even with discounts (would be upwards of £100000 - don't forget the ridic expensive ceiling peel, £12k was it? ) - she would have had to have had help
Flora also hasn't made that much money from instagram to afford a deposit. Even buying with fossil boy.
Let's not forget, they have considerable generational wealth so they'll all benefit from at some point - some sooner than others.