UCAS - Wrong Grade

I've recently submitted as a mature student and realised too late that I have put the wrong grade on my A-level results (I got an E in Spanish, but I put D). Is there any way to correct this? Or will it affect my application?

You can correct that grade via this form on the UCAS web site.

(In fact, you must correct that grade. Otherwise, when the university you ultimately join asks for evidence of your exam results they may well feel that they were misled and would be fully within their rights to withdraw the place at the last minute.)

Thank you for your help! It's all sorted now :-)