What you have is a manual selector valve that either selects the input for the loader valve or the BH .
If you remove the BH, there is no need to connect hoses, just leave the manual valve in the loader position, and you will also have 3pt.
If you remove the manual selector valve and feed the loader with the pump hose, that is the normal mode.
A different way to connect the BH is to take the PB from the loader and feed one line to the back for the input to the 3pt.
Then a hose from the 3pt input to connect to the PB on the BH valve. if the BH valve does not have a PB port, then the OUT on the BH valve will go to tank. If the BH OUT port goes to tank, then cap the 3pt input hose and you will not have any 3pt.
With this setup, and you disconnect the BH, then you ;would connect the PB hose from the loader to the input to the 3pt.
What they should have done , is to connect a long hose from the hyd blk to the rear for the BH, and another hose from the BH OUT port back to the hyd blk for a complete flow path.
Recommend you remove the water pipe fitting and use hyd fitting
Then when you removed the BH, you would have connected the hoses from the BH valve together.