From 2017 to 2020 ERCC's income doubled. Interesting - change in the business model? Or maybe a jump in funding due to Covid? Anyway, almost all the income in 2020 (just over £800K) is from grants/SLAs from local or national government or other charities, NOT donations (donations were only £40K. Doesn't seem a great hit rate for donations but don't know what's typical).
The single biggest funder in 2020 is the Scottish Government, naturally - about 40% of their grant income is directly from SG. The single biggest grants by value are from the lottery (£170K) and Comic Relief (£86K). Overall the income splits out as (very roughly) about 50% income from government bodies and 50% from other very big charities.
Interestingly there was a small grant from JKR's charity, the Volant Trust!
Basically, ERCC would not have a hope of continuing to function as the organisation they have become without the government money. The lack of financial independence from government is a huge problem for these kinds of charities I think. From a financial and delivery perspective, it would almost be more accurate to say they are arms' length bodies of government. Which is not necessarily a comfortable place to be for a social charity.