Well the good news is that your GDI Plus 4 has an external clutch slave cylinder accessible for checking and bleeding outside of the clutch housing.
I would start as suggested above by checking clutch hydraulic reservoir fluid level. Although the reservoir (3) is clear plastic the clear colour of fluid can be difficult to see without taking the filler cap off. If it is low check for leaks on clutch master (2). Screenshot of parts book below to identify parts I'm referring to.
![[Linked Image]](https://i.ibb.co/x8rB92N0/Screenshot-20260625-132142-Adobe-Acrobat.jpg)
If fluid level is low but no leaks seen in vicinity looks for signs of leak from slave cylinder underneath left hand side of car between engine and gearbox.
Any competent garage should, as a minimum, be able to identify any failed part once car is on a ramp assuming the problem lies with clutch hydraulics.