I found some Finger Lime Seedson Amazon; I hope they ship to Europe. I also found an article about finger limes being introduced to to Europe. The article mentions the Hermanos Mantes company receiving fruits from the Prime Tropics company. So, Prime Tropics might be a possible option, maybe, for obtaining trees. Whereas, Hermanos Mantes might be an option for getting the fruits.
I live in the (tiny) natural range of finger limes.
Unless its grafted, they do not like to be treated like other citrus, its a rainforest plant and prefers light shade.
Finger limes can't handle rich soil amendments like normal citrus.
They are slower than other citrus, spikey and much less productive.
Many gardeners fail with finger limes, even here where they evolved, simply by treating them like an ordinary citrus.
Having said that, the texture is amazing, the pulp is great in a gin & tonic and the price of fruit is eye-watering as the market demand simply cannot be met.
Examine your lifestyle, multiply it by 7.7 billion other ego-monkeys with similar desires and query whether that global impact is conscionable.
It would give a normal human mental abilities to rival mine. To think it is just a tiny ad:
It's like binging on 7 seasons of your favorite netflix permaculture show