The bow roller on my B36(2002) has a transverse pin that goes through the two side plates and which is located right at the aft end the bow roller. I have had my boat on a swinging mooring throughout the season from April to October each year since 2012 in Holyhead harbour in North Wales. Up to now the mooring had only a small spherical buoy to mark its location, and which was lifted onboard where it stayed all the while the boat was moored. Sea conditions within the harbour can get quite lumpy, particularly during strong north easterlies, but that transverse pin has helped ensure the mooring remained in place at all times. Note, the anchor has always been removed from the bow roller prior to mooring the boat, and was stored on the port side out of the way of the rope from the mooring all the while the boat remained on the swinging mooring. This ensured that the mooring rope itself was not damaged due to chafe while the boat remained on the mooring.
In order to minimise any side thrust on the bow roller the mooring rope, which was secured primarily to the starboard side focsle mooring cleat, was also supplemented with a separate rope taken from the port mooring cleat and around the mooring rope to pull the mooring rope to the centre line rather like a “Y” shape set up.
As for a removable roller, again the transverse pin referred to has been used to hold an ATN tacker in place for use with a cruising chute during light winds and has been managed during single handed sailing.
Sorry, I have no photos currently available to include with this posting.