Tax on UK pensions for expats who are resident in South Africa?

I am a 49 year old UK citizen with a national health service pension and a private pension (SIPP). I am planning to emigrate to South Africa and (being married for 7 years to a South African Citizen) become a South African citizen. We plan to work and then retire in South Africa. As I will no longer be a UK resident my pensions will be paid gross of UK income tax. How will the lump sums and monthly payments be taxed in South Africa?

The pension received from the UK will be exempt from tax in SA. Bringing in a lumpsum will also be tax free, however the investment income earned on this in South Africa will be subject to tax.