Is it possible to connect this wall light to the existing fixture?
Turn off the power at the wall switch. If there are others in house while you are doing this, tape the switch in the off position or attach a note to it, and inform all others in the house that they are not to flip this switch while you are working on it. Safer yet is to turn off the breaker to this circuit in the consumer unit. 

The black coloured connection block looks like it is in the light fixture and, if so, I suggest you use it. Remove the other connector from the brown and blue coloured wires and insert them into the appropriate holes in the black block, and secure them with the screws (firm tight but not so tight you break anything). Insert the earthing wires in the middle hole and secure. Test by turning on the wall switch.