Like I said had two dudd coils in the past!
Its a simple system of elimination plugs, HT leads, dizzy cap, king lead, coil, power. Working your way up is the only way you can diagnose this and rightly said from someoone
if an earth is not properly mounted to the firewall it will not spark. I bought two coils brand new from motor factors both were gone third one fired right up the chap who sold me the coil even came down to see what was wrong and bought the third coil down to me wired it up fire up good, re-wired the old new ones dead as a dodo!