Johnnychips is right. there is only ONE flight direct to Barcelona, Monarch. Next year there will be Jet 2 on 4 days a week.
Many people connect to/from BCN because of flight timings. I use Monarch alot-but also use Swiss via ZRH, who can also often be cheaper than Monarch.
I Certainly would not pay for J class on a shorthaul flight.
But Johnnychips you can use the BMI lounge, but the lounge is situated near gate 18 & the BSL flight usuallly goes from gate 53 a fair distance away.
I have also traveled on the BMI BSL service, which had very poor loads both ways & there was not even a cabin divider between economy & business class, mind you there were no J class pax either way.