Correct, just LBAJER, no MAN/BHX/STN option.
They've been dipping their toe in the water with the shorter flights (EGC and LRH). so it might be on the cards, who knows?
The big problem for them though, is would they be able to fill a B738 on these short sectors (since Jet2 are phasing the B733 out and MAN/BHX/STN have no B733's based). 189 seats might be too much for them.
Routes like that would be better suited to smaller A/c. Flybe's -8's and E-jets spring to mind as suitable, but they're just incompatable with Jet2 and their core market