As far, as I remember that's at least the third time @Anthony_Craig tries to solve his problem with (the absence of) meteo-qt notifications. He suspects that the root cause is a "notification service" and intends to have the service up and running.
I'm sorry to be pessimistic about that, but I feel an urge to warn against fruitless efforts. Here is why:
First, the post Sudo password not required - #8 by Anthony_Craig clearly shows that the system installed is Ubuntu Mate with KDE Plasma desktop. To me this sounds like Mate DE answers may be irrelevant for the situation.
Second, It looks like Mate notification service has little to do with KDE-based application and its notifications mechanics/implementation.
P.S. Please ignore my post if you feel that my reasoning is not correct.