Sick Pay for small organisation

Hi All,

I am seeking advice for a sick pay policy for a small organisation with 5 part-time employees and unpredictable income (dependent on the success of grants). Furthermore, the organisation includes employees who have been there for decades, and others who have only been there for a couple of months. We also work different hours (some only work 7 hours a week, and others up to 28 hours a week). How do we construct a sick-pay policy that is inclusive and fair while considering all of these factors?
I am thinking of suggesting that we add the below wording to our employment contracts - I am open to feedback and any suggestions.!

Best wishes,

If you are unable to work due to illness or injury, it is imperative that you notify X at your earliest convenience on the first day of absence, and provide regular updates thereafter regarding your inability to work. Initially, you are permitted to self-certify your absence for a maximum of 6 working days. Beyond this period, a Doctor’s Certificate must be obtained and submitted.

As per your contractual agreement, you are entitled to receive sick pay for a duration of up to four weeks (pro-rata in accordance with your contract). During the subsequent two weeks, sick pay will be granted at a rate of half your usual pay. Following this period, statutory sick pay will come into effect.

To illustrate, if your contracted workload is 7 hours per week over 4 days each month, you will receive full pay for four days in the first month, and two days in the second month. Conversely, if you work 21 hours per week, you will receive 12 days’ pay in the initial month and six days’ pay in the subsequent month. Once this period concludes, statutory pay will take effect.

*It is important to note that (the organisation) retains the authority to consider discretionary sick pay on an ad hoc basis. This consideration will involve factors such as your tenure within the organisation, the severity of your illness, and any financial hardship you might be facing. *