With the Great Northern and Park Lane going up to Cat 6, it looks like Central London is now 100% Cat 6. Yikes. Though I suppose it actually makes life easier in some ways, because those two hotels have some significant disadvantages (tiny rooms and general oldness respectively, though with the renovation the Park Lane might have gotten better), so at least now I wouldn't feel bad shelling out Cat 6 points for one of the other properties in London.
But regardless, Lurkers thanks for posting and alerting us -- always appreciate the opportunity to get in some last bookings at old rates.