Step 1a; The Blots & Blemishes, away they go!
Using the Clone Tool is quite simple. Once selected, the tool appears as a circular cursor. Positioning the cursor on a piece of unblemished sky, a left mouse click, while holding the "Alt" key copies the area of screen beneath the circle. Now move the cursor over that ugly blob near the top of the image and click the left mouse key; this time without the "Alt" key. Compare the 2 images; typical "before & after" shots. The blemishes have almost all gone but there is still a tricky looking blob at the mast head.