I am wondering whether I should remove the pump and dismantle it or to just ride and see how it goes...
I did notice it seemed quite hard to fill the system if just pouring water in to the top once the drain nut was back in place - it kept making 'I am full' noises at me after only half a liter or so. I had to keep on squeezing the pipes to get more to go in.
Use of a coolant flush product—if you haven't used one yet—might help rinse out whatever scum is hanging on in the coolant passages. If it were my bike I'd do a couple more flushes with a product like that. You run the engine using them. Then I'd ride it to see if the pump leaks, if it's at the riding stage. Otherwise, ¿Quién sabe? You can always rebuild the pump, which is what you'll need to do anyway, if you compromise any seals. That means new seals
and a new impeller, among other things.
The radiator needs to be filled slowly; I use a funnel. The squeezing technique is normal procedure and expected.