Thanks very much to guidance from Martine (see previous piece) I am now able to understand far more of the symbols on the Sacristy Crucifix.

The following is edited from Wikipidea.

(“Weapons of Christ”), or the Instruments of the Passion,
are the objects associated with Jesus’ Passion in Christian symbolism and art.

They are seen as arms in the sense of heraldry, and also as the weapons Christ used to achieve his conquest over Satan. The purpose of the representations was to symbolize the sufferings of Christ during his Passion.
The Instruments :
The Cross on which Jesus was crucified.
The Crown of Thorns.
The pillar or column where Jesus was whipped in the Flagellation of Christ.
The whip, used for the 39 lashes.
The Holy Sponge set on a reed, with which gall and vinegar were offered to Jesus.
The Holy Lance with which a Roman soldier inflicted the final of the Five Wounds in his side.
The Veil of Veronica
The Seamless robe of Jesus .
The dice with which the soldiers gamed for Christ’s robe
The ladder used for the Deposition (removing the body of Jesus from the cross for burial).
The hammer used to drive the nails into Jesus’ hands and feet
The pincers used to remove the nails.
The sun and moon, representing the eclipse which occurred during the Passion.
Thirty pieces of silver (or a money bag), the price of Judas’ betrayal.
The hand which slapped Jesus’ face.
The sword used by Peter to cut off the ear of the High Priest’s servant

This means the only symbol I cannot recognise is the lion at the top of the cross, unless there is any way it could be a cock, often placed there to remind us of Peter’s betrayal.