@Douglas Fir Ive not bought anything from them but planfor.es sell tridents (amongst loads of other things). Based in France but deliver to most of Europe I think. Any reviews anyone?
Great info there Shibui.
I've bought quite the bunch of plants in Planfor, can say they offer excellent service and good healthy plants, but their shipment costs are what throws me back.
I´ve been looking recently and found out that they got really cheap trident maples, but for now I'll stick with a few Acer Rubrum I've bought.