The Dunelt brand was (is?) owned and manufactured by Raleigh. The bike you have is basically the same as a Raleigh Record, so basically any information you find about the Raleigh Record will apply to yours, more or less. The serial number should be a Raleigh serial number, so you can look it up as such.
Sure looks like a Raleigh to me. They got bought out before 10 speeds got popular. Try referencing the serial number and if it lines up with the Raleigh charts you'll know. If it doesn't then it might actually be a Dunelt Dunelt.
Round here, with good tires and fresh grease in all the bearings I'd get $125 for it but they'll bump you to the What's it worth forum for asking.