Just to correct 2 bits of mis-information:
1) NATS have not 'closed' the whole of UK airspace; the CAA have directed NATS that IFR clearances are not to be issued thus effectively denying the use of class A airspace.(this includes class A CTRs where SVFR clearances are also not permitted)
2) In other airspace classifications, you can (and indeed many aircraft are) still fly VFR but the CAA have directed units providing ATSOCAs in class G airspace that services relying on radar are not to be provided.