I am having trouble creating a flightplan when adding waypoints.

I can't prevent LMP from adding the waypoint as the next waypoint from the SECOND LAST waypoint added instead from the last waypoint added - hope you understand what I mean.

I have seen a video tutorial creating a flight plan using the MSFS flight p0lan creator where the same thing happens and the author mentioned this and states to simply remove that waypoint and add it again and MSFS will correct the 'problem' yet when I try the same thing in LNM it doesn't fix it.

Surely there is a method to use which I cannot work out.

 

 

Not  sure if I understand. I suppose you edit the plan manually, right?

LNM adds waypoints into the nearby leg or before departure or after destination. Depends on click position when using "add" from the context menu (or Ctrl+Alt+Click).
The append function (or Shift+Alt+Click) always adds at the end of the plan no matter where you click. More about this clicking stuff here: https://www.littlenavmap.org/manuals/littlenavmap/release/2.6/en/MAPDISPLAY.html#add-position-to-flight-plan

Now the other edit mode (menu "Flight Plan" -> "Edit Flight Plan on Map") is a different thing and allows to click and drag new points (click on a flight plan line/leg) or move points (click on a flight plan waypoint). See here about this edit mode: https://www.littlenavmap.org/manuals/littlenavmap/release/2.6/en/MAPFPEDIT.html

For sure there is no need to go through the MSFS planner.

Alex