Thanks Sdcarver and SGS man - following your valuable advice I went straight to spg.com to book the room. The only wierd thing was the different price options... For some very odd reason the "luxury" package where they give you a bottle of champagne and flowers etc is cheaper than most other deals because it clearly states that all extra taxes are included. This means that there is virtually no advantage in paying in advance - this luxury option is much better and is changeable..
Decided to go for grande deluxe because this time I really do want to be gauranteed my decent room - although platinum very rarely lets me down..

Lets hope I get my late checkout after 4 pm - as with most Europe bound flights my flight leaves BKK very late and a 8 pm checkout would be very appreciated
I let you all know in June how it went - thanks again