As Dzug says, the only way you can change it is if you apply for a completely new passport, in which case you'll have to declare the old one as lost.
The only time that passports can be replaced for a change of photo is in the case of children, whose passports can be replaced after five years.
I think it's standard form that a) you always look like a demented gerbil on your passport photo, b) officials always have a laugh at it, and c) you're not supposed to like it.
I hate mine too, and it's only a couple of years old. But it's not as though I have to look at it every day.
Don't worry, Allied, you only have another five years to go, and you can change it when you replace the passport