The first thing to know about NHS treatment is that it is based on where you are resident, not where you were born.
Therefore, if you are resident in Poland and need to use the NHS while visiting England, then you may still need to pay, even if you were born in England, lived there in the past or continue to make voluntary National Insurance Contributions.
The following comes from the main NHS website:
If you are a visitor from the European Economic Area (EEA) and you fall ill or have a medical emergency during your temporary stay in England, then you’ll need a valid European Health Insurance Card (EHIC) issued by your home country. If you can’t show a valid EHIC, you may be charged for your treatment.
Finally, it is worth noting that if you are travelling to England specifically for planned treatment or to give birth, then you will need to make all necessary arrangements in advance. Planned treatment (including giving birth) is not covered by the EHIC. Therefore, if you do not have valid documentation, you may be charged for treatment.
You can find out more about NHS entitlement while visiting England from Poland here.