Remove trigger, bent &spring, invert & lube threads with Dri Slide, leave 24 hours. Wrap strong cotton rag aroung cylinder ensuring some of the rag is wedged inside the cyl through the cocking slot ( this will stop the cyl turning & give a firm hold dont try vices you will bugger the cylinder) use a large hard rubber mallett & strike the trigger block untill it becomes free. Be aware the threaded portion of the block is steel and can sometimes seperate from the ally block, look it up for detail. Oh & mebbe use a strong leather glove when holding the rag wrapped cylinder.
Goodluck bud!
H