Was it bare root wips you planted? All wips take 1 year to get growing, the first year, esp in heavy soils, will be root growth, the second more leaf and the 3rd will really come on. I just dig a trench, add some compost and bonemeal and water (not this year as it has been so wet) and leave it to grow.

I planted one a couple of years ago and some plants lived and some died. Those that lived developed at different rates. I had to buy replacements for the dead ones but they were not copper beech as the tag said, so now I have both types.

Thanks for replies.
these were bare root stock - 2+1 (I think that's how it's described in the business). I planted last November with plenty of compost and bone meal. Can you use Miracle Grow on young beech trees?

From experience, I found my beech hedge slow to get going for the first couple of years and then suddenly took off. You set it well so you would that would be sufficient to get it going.