Picture attached is a French front and back number plate not UK. but its European Union style you can say. EU has agreed with such plates because cars/truck move from one country to another freely and easy to understand the reg plates, they all have different reg systems though!
Thats not the case in Pakistan, hardly a Pakistani registerd car can get mixed up with others or into another country! except Pakistani or Afghani trucks crossing into eachother borders.
Pakistani plates are more like the Switzerland or the US states one, where every city/region has its own emblem embosed on it, other difference Registration of cars is still a provincial and district oriented and controlled. We dont have a single national registration authority which will be good, but we have only provincial authorities for tax purposes
Colors are defined by law, Pakistan has mostly difference between private and commecial vehicles with no difference in front or back plates.
However nothing stops you from getting a customized plates, but you may be stopped by Police here and there for this.