Thanks for the reply!
I always use the flush at the same place with the same pressure however now I have a plugged jet and have not yet figured out where I can get to it to clean it out.
If it means dropping a tank, then I won't be doing that!
The way the tank is mounted, inside a compartment, I can see the front with the tank level sensors, the right side is against the grey tank and the left side is against the side wall of the compartment. That only leaves the top or the back side.
I'll probably try filling the tank with water and some cleaner and then drive around for a while to see if it dislodges whatever is stuck in it!