Move the heater. It’s not wise to block heaters.
I know it’s a water system, but if you can cut it out and move / extend the lines I would do so.
The only other option might be to box around it and redirect the heat out with a small 12vdc fan running on low…or create an opening at the top of the box to let warm air out and create a convection current…or even integrate the heat into the bar.
One last thought…just butt the short side to the wall and the overhang should still allow the heater vent to clear. Remove the foot rest on that side too. Do so by simply ommitting the foot rest parts. Study the plans and you’ll understand how to do this quite easily.