[Big lip on print. Not sure what to do]

Brillian. Thanks for the tips I'll take a look.

[Big lip on print. Not sure what to do]

Hi, first post and first time using the Cura software. I printed a project for my son last night. It was a desk with drawers and he broke all the pieces out into separate components. It looks something like this. 

 

 

I selected support and adhesion, which gave me something like this once sliced and previewed. 

 

 

But when it printed everything seemed to have a misplaced bottom layer, where there was a big lip sticking out at the front and a gap at the back, as if the bottom layer had slipped. 

 

 

Is this meant to happen and I'm supposed to remove this layer, or have I done something wrong? Apologies for the basic nature of the question. Like I say, it's my first time working with this and I'm learning as I go. Oh, and the printer is a Geeetech A20M.

 

Many thanks for reading.