My element simply wont stick upon scrolling ?!

Unfortunately i come from using unbounce for landing pages so i have very limited website development knowledge. However, i cant for the life of me understand why my image is not ‘sticking’ when i scroll down.

I dont know if its perhaps my layer arrangement (Section > Div Block > Div Box > Image), but the idea is that the image sticks as the text in an adjacent structure carries on scrolling down.

I’ve made sure no overflow is ‘hidden’ and that no parent has any fixed height, and that the element has plenty of room to move down as it sticks but still …no luck.

Any advice on my link would be greatly appreciated:

The image / Div box in question is the one a quarter down the page next to the text titled ‘what we do’

Im currently just messing around with templates but stressful none the less…

Thanks everyone!

Here is my public share link: LINK
(how to access public share link)