iMac LCD fault after cleaning, lower half of screen useless :(

I purchased an iMac through a private sale last week and noticed some 'clouding' or 'smudging' in the top right corner of the screen on light backgrounds.

I researched the problem and have found that the solution is to clean the LCD glass and panel therefore having to dismantle the iMac. Since the iMac was purchased way back in May 2012 it is out of warranty.

Good news is I was able to get rid of the clouding/smudging in the top right corner - bad news... when I booted up the iMac after putting everything back together again I am greeted with the lower quarter of the screen as 'grey' with horizontal lines.

I figure that I have damaged a circuit or one of the five bands that project the display onto the LCD panel. There were four connections I had to click back in from the screen to the circuit boards on the iMac.

I have checked the connections several times and blown out any dust and still have the issue. The rest of the iMac seems to be running OK but not much fun with only 70-80% real estate on the screen

I know that I took the chance in doing my own repairs but being out of warranty and viewing the guides on iFixIt and YouTube I felt confident in being able to do the repair. Below is a photo of what the screen looks like on startup.

Regards, Shaun

iMac on startup

iMac in use