WillWork4Parts
I live for the CABE
Being a lightweight bike makes things a lot more delicate.... Not sure about a Raleigh, but hopefully a chromoly fork? That would help in the twisting department, just be careful not to bend the fork if it makes it to a vise. Worse comes to worst, the aluminum stem may shear, but that will allow you to remove it from the bike and cut or drill broken pieces out. If you are 100% sure the wedge moves up and down freely, you can try tapping the stem down with the wheel off and the fork backed up on something solid. ANY movement is something to work with, especially if it's corrosion we are dealing with. If you see it move, start twisting back and forth and don't give up, every little bit counts! I fear heat might soften the aluminum, point the torch down the stem bolt hole if it suits you though.