Quick flour question

[WingMirrorSpider]

I'm making shortcrust pastry and only have 400g plain flour left (I need 650g) I've got plenty of strong bread flour though. Can I substitute 250g of this or do I need to send DH down to Tesco?

It might make your pastry a bit tough, I guess it depends what you are using it for, if it's just a pie lid I'd go for it but maybe roll out a little thinner, if a tart or something I think I'd head for Tesco!