OK i downloaded and installed Notepad++.
Pasted some code from the IDE into Notepad++ and it pastes correctly, though i don't see anywhere in Notepad++ that tells me the line ending being used.
Pasting the exact same clipboard contents into Notepad pastes it all as a single line.
I was just thinking - this problem appeared at the same time that i installed the windows version of gedit. I doubt that the gedit installation modified any windows files BUT it is possible.
So i ran the windows System File Checker and tried pasting into Notepad again - it still pastes the code as a single line.
Martin.