Drawing Issues

Hey Dan and people.

I have an issue with my bot. (see link)

When i draw with the bot it doesn’t stay within the boundaries when i want to draw a boundary like you do in the demo video. it goes the the far left and then moves up even though its A4 paper i am doing a boundary for.
Also,
The drawings seem bowed, See image in link.
is this normal???

and lastly when i draw 100mm line it gives me 130mm or variations of that.
i played with the diameter settings and get close to 100mm but then i move 100mm in the other direction and it doesn’t do it the same length..

any thoughts on this problem?
cheers

https://photos.app.goo.gl/2n5jFYwTjwy9tlUr2