No no no
Gift aid is to registered charities - and used to be limitless but may well be down to £25 000 per year. Records should be kept and you should be paying tax
(you cant giftaid if you pay no tax)
Giving to your children and grandchildren without IHT liability is different
(altho I agree that giving to them is in fact.. er ,, aiding them)
and is dealt with here
http://www.hmrc.gov.uk/inheritancetax/pass-money-property/exempt-gifts.htm
read it
it is something like £250 to each child in addition to the aggregated £3000/y
grandchildren less
marraige of children more
simple really
Remember these are out of capital
so long as you can show convincingly it is out of income - then any amount so long as it does not decrease your life style - see the sheet - a commonly forgotten rule