Hi Joan, the way to respond to an answer is to make a comment in the box below the answer. Unfortunately you have not answered the questions I asked, is the red acer in a windy position or in full sun and are the green acers Japanese acers or not? If you have Japanese acers in a windy or very sunny position their leaves do burn and drop off and the red varieties are more tender than the green ones.

Hi again,

I live on the North East Coast about 200 yds from the sea. The Acer is situated in my back garden which is a little more sheltered than the front but things do still catch the wind and cold. It is probably as you say the wind that it is finding it hard to tolerate. Thanks again

If there is any likelihood of salt spray the acer definitely won't tolerate that.