Thanks for your responses...We may have a solution for the worse effected area, someone has suggested a outside vacuum which worked for them.

I had a word with our neighbours (English) last year about the problem because some large boughs from their trees have fallen into the field...I consider this as fairly dangerous but they obviously don't ,as they have not done a thing about it.

The boughs are too high and large for us to do anything about...so perhaps a trip to the Mairie to find out about our rights on this particular issue, is the way forward....

thanks again