Squirrels in the garden

Question from Rosemary Whyte

We have recently removed red chips from an area of garden and replaced it with new top soil and membrane to reduce weed growth. We planted new plants and put down chipped bark. Every morning since we did this we have found large patches where the chipped bark has been scraped away, the membrane pulled up and in a some places has been chewed. I am blaming grey squirrels of which there are many in this part of the country (Glasgow). So far they have not damaged any of the new plants and the disturbance is cosmetic but I know the type of damage they can do. Can anyone suggest how we deter them from this part of the garden?