I find the reversing light offers very little light.    Contributory factors are that the area where I park my car is pitch black at night but also the light is housed on the left side of the rear panel.

I had a quick look in the Forum search section and found a topic from may 2014 regarding rear fog/reversing bulb installation/replacement  which fizzled out with no real conclusions.

Can anyone help on this? The manual states that the reversing/rear fog lightbulb replacement is a dealership issue.

I just want to get a better quality reversing bulb in there. If anyone can also recommend a better quality W16W bulb I would be grateful.

I dont think the light will ever be bright because of the size. Don't cars have reversing lights just to indicate that they are reversing? Might be a daft question but just wondering. I should imagine the bulb might be a weird size because its a garage job. Personally I would invest in an outside light on the house instead of trying to get a better bulb. If you go too high on the wattage you could burn out the unit.

You could try an LED bulb? Using only one should work and not throw any errors.

According to my research, which may or may not be correct, it appears to be a capless 921 fitment 12v 21w lamp.

There are LED versions available but I do not know if they are bright enough.

As the regs dictate no more than 24w of an ordinary lamp, I suspect fitting any sort of non E marked LED would be frowned on.

How about fitting a pair of these, set into the rear bumper
http://www.carbuildersolutions.com/uk/95mm-led-reverse-each