You’re falling into the common trap of treating “PAYE” as a synonym for “income tax”, but it isn’t. The PAYE nominal is where your payday journals should put all liabilities that are settled through Pay-As-You-Earn, which includes income tax, employees’ NI deductions, employer’s NI contributions, student loan repayments, etc. etc. It’s a catch all for all the things that you pay to HMRC as part of your once a month PAYE payment.
There may be a separate balance sheet nominal labelled “national insurance” but this is generally only used for NI liabilities such as class 1A that are not part of the regular PAYE cycle and are instead settled by their own separate payments to HMRC.
I’m not sure why the support example splits the different PAYE liabilities into separate nominals on the balance sheet, that just makes things far more complicated than they need to be.
This is a similar situation as with the PAYE nominal above - the “Employers pensions” code is a P&L code that represents the additional cost of employer contributions on top of the employee’s gross wages, whereas “pension fund” is a balance sheet code representing your total liability to the pension provider for both the employer and employee contributions. Your payroll journals would typically debit employer pensions with the employer contribution, and credit “pension fund” with the sum of the employer contributions plus the amount you have deducted for the employee’s own contributions when calculating their net pay.
When you pay the combined contributions over to the pension provider those bank transactions are tagged to “pension fund” to net off the liability that was created by the journals.