Hi Watson,
When your wife accompanied you to the overseas soverign base, she left the UK for tax purposes, even if you are housed on the base.
She would be able to pay into her pension scheme up to the maximum of £60,000 or her annual earned income if lower in the tax year that she left the UK.
After the tax year has ended, she would only be allowed to pay in a maximum of £2880 into her pension scheme and receive tax relief, plus any unused allowance carried
forward from the 3 previous tax year (
PTM055100 - Annual allowance: carry forward).
If your wife commences receipt of her pension and it is a non UK government pension, then it may be taxable in the country in which the base is located and not in the UK.
Your wife will need to check if there is a tax treaty with that country (
Tax treaties) and use form DT-Individual to apply for relief at source from UK Income Tax and to claim
repayment of UK Income Tax (
Double Taxation: Treaty Relief (Form DT-Individual) some countries have a specific version that should be used.
Thank you.