clearly i'm not the Astraeus expert you were looking for! Astraeus have two 737's at LGW. G-STRA (300) and G-STRE (700). I wouldn't worry about the 320 quid difference in selection prices when the final cost is so enormous. after all, in both cases the selection money is creditted to your final bill, and presumably you won't be going for the selection unless you think you stand a pretty good chance of getting through.