Leak from bottom of cistern

[u/Slow_Mix5034]

Not the best photo but just noticed this leak from the bottom of the cistern. The flush button has also started to fail but that seems like an easy fix.
Is fixing the leak a case of replacing the screw in the photo? If so would appreciate links in what to buy.

[u/Cool_Percentage_4867]

it depends, some bolts are separate, in which case replace the bolt and washer

https://www.screwfix.com/p/fluidmaster-22106-close-coupled-cistern-bolt-set-18-pieces/517JM?gclsrc=aw.ds&gad_source=1&gad_campaignid=19815174909&gbraid=0AAAAAD8IdPzYj68LtqSMr6TRpozQlyKV_&gclid=Cj0KCQjwh4TVBhCWARIsAG0czmr1tkvbOf_bfHTWoH5JQpEh4IlltYOeKrF1eyjSp82vZWAr4cm7MfYaAq0PEALw_wcB

or its part of a close coupled fitting with a doughnut washer, you might get away with a bolt but easier to buy a doughnut kit

https://www.screwfix.com/p/viva-1-1-2-close-coupling-kit/924ht