SVO is in Europe for OWE calcs. However, you can only have one trip from London to far off European destinations, and DXB and SVO are both in the list that are restricted. So your OWE can include either LHR-DXB-LHR or LHR-SVO-LHR, but not both.

Yes you can purchase a CPH-LHR-CPH far to fit around your OWE.