Paul's V-C back-action - If I read it correctly, the mainspring should be just above the connecting screw


H&H back action as found on Hallowellco


Purdey back action as found on DGS


Purdey - Beesley as found on Hallowellco


Gastinne Renette back action as found on Hallowellco

Seems it all depends if you fancy a back action sidelock or a bar action sidelock and how you define the pins, pegs & axels

Kind Regards,

Raimey
rse