Roller Blind Mounting Bracket (PL4)

Hello my sister bought a roller blind for her room and started putting it up only to discover one of the mounting brackets is missing.

The part we need is outlined in red in the included image.

If anyone has a blind they no longer need or are throwing away which has these type of brackets and you were willing to let me have them please let me know.

I am in PL4 Greenbank and can travel a certain distance to collect it.

Any offers will be greatly appreciated thank you.