Also, move this to the Electrum section for more help: https://bitcointalk.org/index.php?board=98.0
At a glance, I suspect what happened is you did not disable "change address", so when you made your spend, the remainder of the input used was sent to a change address (still within control of your Electrum wallet). This is likely the output you saw.
To confirm this, simply view all your addresses in address tab>all. You should see that output in one of the addresses there.
Oh yes I do have change address enabled! Sorry used Google Drive and shared links. I'll disable that and check it again. Didn't perform a transaction due to fear of losing too much money using fees!
Would make sense that the rest of the money would then be sent to a changed address. You're a star thank you!