If you seriously think Help, Penny Lane, Taxman, I am the Walrus, Back in the USSR - and many more - are skiffle, Scouse or otherwise, then you must have something seriously wrong with your ears.
You might not like them, but they're no more skiffle than they are drum and bass, R'n'B or Country...
Another example that goes to show that the excellent, exciting, wonderful, magical, ground-breaking Beatles were absolutely right to break up when they did.