The Spot removal tool should work in HEAL or CLONE modes by either-
1. A single L-Click to Heal one spot.
2. Hold the Left-mouse button and draw (drag) over any shaped area.
3. L-Click one spot, release the mouse button, then re-position the cursor, hold [Shift] and click the mouse a second time- draws a straight line between the two clicks. (Great for cloning out power-lines on skies!)
4. Relocate the 'Source' area to choose the effect for Heal or Clone.
Both Heal and Clone modes work by providing two circles/shapes-
1. The spot/area where clicked/drawn is the 'Destination'
2. The secondary spot is the 'Source' for the Heal/Clone. (Hit / key to try an auto-locate of the 'Source' )
If you system is not working like this, then maybe resetting the Preference file will correct it.
This form of irregular shape cloning was only introduced in more recent versions: Lightroom version 4 can only do circles.
Thank you richardplondon - that answered my question.