Squeeking pipes/ taps in bathroom

[huliogeordio]

Recently our bathroom pipes began squeeking after flushing the toilet. I thought it was water hammer and ran all taps and turned off the water. This appeared to work but a week later and it's happening again.
The process of event now is, toilet flush > and bathroom sink will squeek and the shower in that bathroom will begin rumbling and dripping. Turning the shower on does not create a sound and only on occasion will turning the bathroom sink tap on will the squeek occur.

Anyway to identify the offending item?

Cheers in advance

 

[king of pipes]

Check the inlet valve in your toilet and the inlet ball valve in any cold water storage tanks in your loft . Kop

 

[huliogeordio]

Check the inlet valve in your toilet and the inlet ball valve in any cold water storage tanks in your loft . Kop

Cheers, it does seem to be the toilet inlet valve as often it can be heard trickling after refilling. I have noticed that pressing the blue plunger on the toilet (image attached) fills the system and stops the trickling. Is the easiest fix just to replace the lot?

Thanks again and apols for the slow responses