So the lever versions are either >>Purdey / Watt<< or >>Manton<< variants depending if the grip lever blocks both the hammer and trigger or just the trigger?

>>The Purdey/Wyatt Patent No.4218 of 1818 blocked both the hammer and trigger. The 'Manton style,' to which
I previously referred, blocked the triggers. J.H. Walsh, author of The Sportsman's Gun and Rifle (1882)
credited Manton with the design - but there is no patent that supports his attribution.<<