The 2011 will is evidence that the 2003 will has been revoked. The fact that the original 2011 will cannot be located does not revive the earlier will.
As regards the 2011 will, who had it last?
If the evidence is that it was in the possession of the testatrix, there is a presumption of revocation. However, that presumption is negated if, whilst the will was in her possession, she lacked capacity. That, though, is subject to there being no satisfactory evidence that the testatrix destroyed, or otherwise revoked, the 2011 will whilst she had capacity.
If the 2011 will can last be traced into the possession of someone other than the testatrix, there is no presumption of revocation and it should be possible to get a grant to a copy will, the grant being subject to the original 2011 will being located.