back payment of pension contributions when not working

I am aware of the £2880 that can be paid into a SIPP each year post retirement from work until the pension goes into drawdown, and that it is subject to tax relief, even if the payee is not a tax payer. However, my wife forgot to make contributions in the 2 tax years passed. 1. Is she allowed to make a larger contribution this year to compensate? 2. If so would the full contribution be subect to tax relief. 3. More generally, is a larger contribution than £2880 allowed - I am aware that tax relief is only on the first £2880, but she is interested in boosting the 25% tax free lump sum in later years - reducing the tax payable on the growth of her investment.

Hi,
 

She can make a larger contribution but as her income is not taxable them the limit of £2880 still applies for tax relief   . Thank you .

Thank You