I think in the case of Hilton HHonors the status you get through Platinum is supposed to last a year >> "Hilton HHonors® Gold VIP membership retention for 1 year without having to earn status". From what you say Neil have you maintained status longer than a year with no stays? Good if you have 
It seems to be only SPG that we're supposed to get beyond a year >> "Starwood Preferred Guest Gold membership retained as long as you remain an American Express Platinum Cardmember"
Incidentally, as far as Radisson Goldpointsplus goes, the AMEX blurb says we're supposed to only get "Silver Elite" status but I seem to be Gold?
Cheers
James

It seems to be only SPG that we're supposed to get beyond a year >> "Starwood Preferred Guest Gold membership retained as long as you remain an American Express Platinum Cardmember"
Incidentally, as far as Radisson Goldpointsplus goes, the AMEX blurb says we're supposed to only get "Silver Elite" status but I seem to be Gold?

Cheers
James