Invoices not put on SA?

I completed my Self Assessment a couple of weeks ago, and submitted/paid
the bill.
Now, doing a little tidying up in my 'office', I've found a small pile
of receipts/invoices that I have paid out from the tax year I've just
submitted - 09/10.
Not a huge total, probably £300ish.

Can I claim these on my next tax return (2010/11), or is it now too late
to claim for these expenses?

Thanks
Alan.

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