Nilfisk Extreme X100 and X150 and X200 and X210 and X300 and Eco on-board accessory lid catch. It's press to release.
Check if tab on accessory lid cover is not broken first.
The part is in the bag as in the photograph. The last photo shows the part removed from the bag.
At the moment standard postage within Australia, is capped at a maximum of $20!