Hi Arbuthnot and welcome to GoY. Sorry to have to tell you the hoeing or weeding out of the seedlings is going to be an ongoing task. New seeds will fall each year and germinate, all you can do is hoe them out...

All you can do is hope the wind's in a different direction towards autumn, so the seeds blow away from your garden.

and for some reason, this year seems to be the worst we have ever had for seedlings coming up. Roll on Ash Die back disease!

I know how you feel. We get Sycamore trees growing in our lawn. Luckily we just mowe them down.

We cut down a huge ash at the bottom of our garden, not only did we, eventually, stop getting seedlings coming up but the difference in light in the garden was amazing. When we bought the house in 1990 the tree had been quite small and it was only looking at old photos and then comparing the height that we realised it needed to go - best thing we ever did. We did keep a 5 foot stump and that has cellmates alpina starting to grow over it with some assistance from Bulba.

We get sycamore seedlings absolutely everywhere - nothing to do but hoe or pull them out.

Agree Stera

Oh well, the answers are just what I thought. It was too much to hope for a miracle.
I, too, am wishing die back would afflict this tree but, knowing Sod and his Law, the disease will kill off all others but this one!
Thank you to everyone for replying.

Well I wouldn't wish a disease on any tree (except the Monkey puzzle) - they do make up in beauty for what they inflict on gardeners. And without them there would be no shade and no leaf mould. I chunter about the sycamore seedlings but the sight of a well proportioned tree in winter against a blue sky is wonderful...

And our sycamores were there before anybody tried to make a garden underneath!

Our gardens back and front have sycamores just over the wall, and anywhere that's not mown is covered with seedlings! But I still enjoy them and appreciate the shade, especially at the bottom of the garden. And they are always full of birds. But those seedlings...

Thanks to everyone for their replies. I, too, love trees, but the one I'm complaining about isn't that old (though it's big enough) so I assume it is a seedling from somewhere else which has been overlooked and allowed to grow at the speedy rate that ash trees do. It certainly wouldn't have been in place when the house was built. However, I do believe is does have die back from what I've read of the symptoms so there's a new dilemma. Do I go round to a neighbour I've never met and mention it? I think it's supposed to be reported isn't it?

yes, its notifiable to the Forestry Commission.

Thank you, Bamboo, I thought it was. All I have to do is summon up the courage to go round and tell my neighbour. Whether she will do anything though is another matter and I'm not sure I can squeal on her.

Well let's hope that when the tree dies, it does it soon and not when its absolutely enormous and a risk to property, life and limb...;-))

If its cut down bear in mind that ash wood makes wonderful firewood and it doesn't need seasoning first, unlike sycamore.
If you are wary of speaking to your neighbour you could send a photo to the Bucks Berks and Oxon wildlife trust to have your suspicions confirmed (or not). They might be willing to advise you what to do as well - its a tricky situation. If you have definite info for your neighbour it would be better than just a suspicion.

Good idea, Steragram, thanks for the suggestion. As for firewood, alas, we no longer have an open fire but then it wouldn't be our wood anyway.

We also had a very large tree problem in the garden behind our garden, it got so large that for most of the summer we had very little sun it was so depressing. We solved the prob by asking the owner if we paid would she let us have it cut down and guess what, my garden is now full of sunshine. Its worth a try.

Well worth the cost to have sunlight in your garden Trixy