The Lucas E3L isn't a bad dynamo. With a clean commutator and free-moving brushes it produces a pretty reasonable output. If you ensure that you have decent earthing - a separate earth wire from your lights to the battery - the lighting is perfectly adequate for night riding. The one mod I have made is to use an LED stop/tail light. It stops any headlight dimming as you slow and brake for a corner.
Check out your dynamo. It's a lot cheaper than going the Alton route.