Add-on shelving unit for Ikea Micke desk https://www.ikea.com/gb/en/p/micke-add-on-unit-high-black-brown-50180027/ . Current price £50.
The backing sheet is slightly warped, but I think this will be flattened when it is secured in place.
Ikea add-on unit for Micke desk (Cotham Ward BS6)
This offer has been gifted to someone and is no longer available.