Broken Vokera Linea 24?

Had problems with not being able to get the central heating going and now when it does fire up, the pressure just skyrockets till the boiler starts creaking.

I've noticed a drip of water coming from underneath also. It's just a slow drip but from the dampness of my cupboard it seem's to have been going for a while. Any help would be greatly appreciated as my house is beginning to get really cold