Between the villages of Cottenham and Histon it is seriously dark and even with solar edge lighting you'll want for more lighting than the weak £20 set outputs.
It's a bit of a minefield buying lights and the technology moves fast and cost has been astronomical. Bear in mind that my product knowledge is very limited.
I have fair number of lights and would currently recommend those that contain LEDs based on on XPG-R5 technology for the general commuter - having a nice friendly spot and enough brightness. For road bikers who travel at speed or mountain bikers riding offroad at night, I would step up to XML-T6 which is even brighter and has a wider flood beam, but not too friendly for oncoming car drivers because of that flood effect.
I am using some cheap (unbranded) Chinese imports that use these technologies but wouldn't recommend that unless you are the type who owns a soldering iron. I know someone who has Exposure branded lights and they are very good quality and also lots of money but will last you years. There are a lot of other good brands out there that I am not familiar with.
My friend has an Exposure Joystick which is based on XPG-R5 and it is bright enough for mountain biking round Thetford Forest at night. If you were a casual commuter you might be able to step down the range but research carefully. Confusingly the Joystick £145, Sirius £115, Spark £95 all run on the XPG-R5 technology, with different amount of Lumens (brightness). I just don't know which would would compare to my cheap Chinese torch.
The lights are expensive but what I can tell you is that over the last few years anyone I've met over the last few years who spent under £100 on branded lights has been disappointed with the light output. Right now, £150 will definitely get you a branded light that meets commuter expectations, perhaps £100 will too but I just don't know.
I recommend looking for sites that compare light output from different lights. Torchy the Battery Boy's light database is a good place to start. You might find your current light on there and beam shots from other lights so you can compare.
Now you know why a lot of people are taking (quality) risks with cheap Chinese imports. Told you its a minefield! Over to the rest of the internet for opinions.