Trees for exposed Scottish Coastal Garden

I have a property on the west coast of Scotland and would like to add some trees to the garden not only for garden interest but also to attract birds. I am considering the Olympic Flame Rowan for a particularly exposed spot and a Weeping Birch for a slightly less exposed spot. 

I am also considering investing in mature trees (average 3m delivered) , but as they are VERY expensive I am wary incase it turns out to be a costly mistake. 

Would welcome any advice on suitable trees, and whether I should just stick with smaller 12 ltr potted stock. 

I also noted from comments a few years ago that people had mentioned Maples which I love, but I thought they would be too fragile for an exposed garden - again would welcome your thoughts.

Thanks