These current gift arrangements may soon be closed down if Labour gets into power, whilst the Tories will expand the opportunities. The gift from net after tax earnings/income (not savings) is not widely known or advertised by the IR, but basically if you earn/have an income of say £100k net after tax annually and have been saving say £50k a year for some time eg 5 years, theoretically under the scheme you should be able to demonstrate why you can give away the £50k or part there of, rather than save it each year.
I'm sure there is plenty of fine print but currently the basic principle holds true, I would talk it thru with a tax expert first to make sure your circumstances satisfy the criteria of the gift..
The difference between the scheme above and the individual annual £3000 gift is that gift can come from any source ie net earnings/income, savings etc.
Remind me - is the £3k per donor or per recipient ie 6k from the two of us shared between 4 grandkids or 3k per grandkid?