Polys are fairly autonomous and have some degree of free play in their policies, even those concerning recruitment.
The principal and higher management set the direction - some are very conservative concerning staffing, while others are more forward-looking and plan ahead for future expansion.
Some insist that new staff can only join at the lower ranks, never accepting a senior or experienced lecturer - that's why you see some poly advertising for 'Lecturer', while there are those advertising for 'Senior/Lecturer' - they really mean what they say!
Leave it for those interested to apply, get interviewed and find out!