We've been over this on this thread a few times now I think, but from what I understand, the standing charge is mostly not related to failed suppliers or supplier debt.
I can't find a source for it but I'm sure someone else has posted one before, and it showed only a few pence was to do with failed suppliers.
It isnt.
The debt was the excuse needed to start a longer term increase of the SC, and I think now most of the debt has even been dealt with.
I dont know all of what has been lumped on to the SC.
But some of the stuff.
Funding to allow suppliers to write off debt, without them needing to take it from their now much healthier profits, or to use the court system. (doesnt go to grid)
Variable grid costs that have been moved from the unit rate to SC.
Funding to allow for unexpected costs, basically a profit margin bump in another name. (doesnt go to grid)
Increased funding for administration costs to the suppliers (this doesnt go to the grid), this includes things like marketing expenditure.
Funding for what Ofgem describe as some kind of adjustment, this as I understand it significantly contributed to the increased profits of the suppliers in the last set of accounts, has been mentioned by some press specifically. (doesnt go to grid)
There is very likely other stuff, but these are off the top of my head what I do know.
The grid currently takes less than half of the SC.
Also currently most political costs related to energy are taken as SC instead of from general taxation. (the one exception being VAT).