There are two types of Raleigh Roadsters collectors. The ones that have had a stuck crank cotter and the ones that haven't had a stuck cotter yet.
"They just don't make them like they use to!" and its a good thing they don't. Stuck cotters are no fun at all. You know it is stuck almost as soon as you start to remove the crank. Pounding on a cotter that is completely bent over from a press usually doesn't help and can bend a BB Spindle.
Time to drill. Carefully cut off the top with a hack saw. Drilling will eventually free a stuck crank, but it can take up to an hour and if your not careful, you can ruin a good Bottom Bracket Spindle by drilling through the flat.
My advice to those in the hell of stuck cotter removal is from a good friend Chris Cooper. Cooper advises to simply ride with the nut and washer removed after soaking the cotter and crank with some kind of thin oil. Surprisingly enough, It works!
Look at it this way, wouldn't you rather ride the bike instead of working on it? This way you are doing both!