I have a client on lowish income plus getting DLA, they qualify for DLA HM.
being offered the chance to start drawing a personal pension and carry on working.
but they need to know if a personal pension will be taken as income for WTC purposes

any ideas

A personal pension will be taken as income for WTC purposes but the first £300 of non earned income e.g. private pension or interest or rental income will be ignored. But the Tax Credits should be calculated on the lower of this years or last years income, so an increase may not make a diference until next year.