This ^^^. Picked up a copy in the Stratford UK store and currently have the chassis finished and half way through the "marriage" stage. Have made Blakbird's MOD and also ensured the gearing is in the correct 1>2>3>4 order, and have taken great care to ensure every axle is free running as I've assembled.
Currently works really well in all gears, sounds fine and no sign of any locks up. Remains to be seen what happens once I've got the full body in place, so we shall see....
.... also v interested to see what Lego do with all the held back online orders, and if there is an addendum / reprint what they will do for those of us that bought shop stock?? Any precedent on this from previous sets???
and I should also say, thanks Jim for the very comprehensive review :)