The H&R was a Webley & Scott (by William Whiting) patent that was never produced in the UK. Patent drawings show an almost exact duplicate of the striker fired H&Rs, which were produced under license by H&R in the U.S.
Just go to your local public library or a local gunshop and see if they have a copy of the NRA Assembly handbooks. If not, they are available from the NRA for a nominal sum. The handbooks cover assembly/disassembly of many different makes of firearms. They are well worth it.