non hall effect throttle in England

[passpato]

I need a twist grip 5k potensiometer type throttle asap. I usually use a Magura from 4qd but they are closed untill new year and then they take their time to ship.I have tried a hall effect throttle but i can't get a voltage out of it.
i am connecting it to a 4qd uni8 5.8 volt feed. The bike is for my mate and he wanted it for Christmas
anyone know of a cheap temparary solution?Or better a shop that sells Magura throttles in the uk. I was thinking of rigging a cheap 5k pot on the bars some how