The old Lincs & Notts aircraft G-LNAA is covering - and happens to have about 4000 less hours on the airframe than G-HAAT..... CAA's G-INFO site notes
G-LNAA had 4069 hrs at Dec09 while
G-HAAT had 8309 at Dec10
But it does make you wonder why G-LNAA didn't go?