Only on Mumset can people turn the OP trying to do a nice thing into an argument and whataboutery.
Yes a lot of people are struggling, and the huge rises in the costs of essentials will have a big impact on some, but not everyone, and posts like the OP, even if you don't/can't donate, raise awareness that these organisations exist, which helps people who need it.
But if you are in a position where you feel you don't need the money, you can donate some or all of it, which you might not have thought about before. Or you could donate some or all of the money to a food bank, who are suffering a drop in donations at a time when demand is soaring.
You don't need to be receiving the money in your bank account to donate the money as your bills will be lower than they would be without the £400 so the net effect is the same. You don't have to donate it all, even if you 'only' donate £50 or £100, that's a huge help to the organisation.
We donated the £150 council tax credit given earlier this year to National Energy Action which is another organisation set up to help people in fuel poverty.
Moneysaving Expert also has a section to help people with the cost of living crisis.
www.moneysavingexpert.com/budgeting-debt-help/
No, it shouldn't be up to the public to help paper over the cracks like this, and there should be more help with improving energy efficiency, which is not affordable or cost effective to many, but that's where we are, so posts like the OP should be taken as a good thing, not ripped apart.