Bathroom wash basin plug repair replace

Although my spring plug operates correctly when pressing the plug it does not seal at all making it impossible to fill the sink and hence having to use wasteful running water. I have tried levering the plug out with my fingers but am reluctant to use too much force. Any ideas how this plug unit can be removed and repaired or replaced. It’s the round sink model fitted to the Broadway fb.

Many thanks

If the plug is the part domed type, it will unscrew. Press down and turn anticlockwise. The seal on the underside can be replaced.

https://www.amazon.co.uk/dp/B09FQ266HZ/?coliid=I1UP318XIPBOSZ&colid=9YN84HWPV43N&psc=1&ref_=list_c_wl_lv_ov_lig_dp_it

Google how to remove push down sink plug, loads of similar instructions.

Thanks for the guidance I’ll get the seal replaced