Crumble topping - no plain flour

[whiteliesaregoodlies]

I have a huge bowl of plums I want to use for a crumble .... but disaster! Am out of plain flour. Will it kill us all to use self-raising? If not I'll make a cake-type topping, but really fancied a crumble tonight.

I use whatever flour I have in the cupboard-makes ZERO difference

Nigella uses SR, I believe.

Thank you! Not a disaster after all.