Matt it would be far easier to just re-condition your other headlight.
All headlights are lacquered, all that is required is to sand off all the lacquer, then re lacquer. Its a bit more in depth than that but its a process we do at least once a week, we do it on brand new audis all the time where people have scarped their headlight and dont want to pay £700 for a new unit.
Re lacquering your old headlight will make it look brand new and make the plastic crystal clear again, it is a VAS (aka VAG) approved product too.
Most places will charge around £40-50 that do this service