I was lucky enough to sit in an F8 at Filton (thanks to my second-cousin war ace John Braham) and fly in a T7 from RAF Chivenor (CCF summer camp).
I had the original Dinky Toy and recall wondering about those exhausts at the time. Can't think of any reason for making them like that.
A later Meteor had alternative exhausts, normal ones at the rear and supplementary ones vectored downward, switched by a flap valve, for short take-off trials.