Hi. My name is*****'m looking at your question now and will post my answer or ask for more information here in a short while.
Your NHS pension exceeds the personal allowance of £11,000 by £2,958 and you should be paying tax at 20% (£591.60) on that over the current tax year, £49.30 per month.
If you take your state pension every 28 days, you will receive 13 payments of £512 in a year. If you take it monthly on the same date, you will receive 12 payments of £554.66 in a year. Either way, the monthly tax deduction from your NHS pension will increase by £110.93 per month (£128 x 52 @ 20% /12). So, if your NHS pension is £1,163.16 per month, the tax deduction will be £160.23 per month and your net monthly NHS pension will be £1,002.93 (£1,163.16 - £160.23). The state pension is paid gross so you will receive either £512 or £554.66 per month depending in how often you choose to have it paid to you as described above (every 28 days or monthly on the same date).
I hope this helps but let me know if you have any further questions.