Need to repaint the black plinth around the bottom of the exterior walls

Fill it taper it out

If its solid & wont come off without scraping it back to bare render then you can just go straight over it with new. If however you dont like the edges of old showing through the new you will need to scrape it back first. If you go back to all bare render then it would be a good idea to apply a stabilising solution to the render first, before applying your new Black masonry paint. Wickes do a good priced stabiliser.

wire brush all areas then stabilise primer then do any filling to feather out.

Use a stabilizing solution first before you paint it to seal the wall