3 months full and 3 at half is very generous, I assume you are going from public sector to private.
20 days in the private sector is still very generous, most will state at managers discretion and only provide statutory sick pay.
^^ very much this – I am public sector and my wife is private sector. She isn’t guaranteed a single day’s sick pay, so there is a splendid financial incentive for her to come into work with flu and spread it to everyone else. Which is what happens. One colleague had to go into hospital (for an operation, not flu) and still only got statutory 😐