Not quite tax free.

I will 'earn' £28k, £10k from ISA, £18K from pension.

£4,500 is tax free lump sum and leaving 13,500 of taxable income.

Next year the personal allowance is £12,500 so I need to pay 20% of 1000.

Or £200 tax.

The 100k drop in wealth reduces my income to £24k so no tax will be payable then.

The real sign of middle age. You start doing pension calculations.