@Till
yes, this is actually the same tree from which you got a fruit back then and from which I photographed the fruit last year
By the way, after the fruit I gave you, the tree has stopped growing, so first not for a while, then a fruit has grown and now there are more and more fruits per season, I think now the tree is stable adult.
Don't worry that you didn't get in touch with me anymore, it happens, although I am glad that you can still remember me, and I regret that you didn't keep in touch. But it is just human and also due to capacity that one cannot keep all contacts alive with the same attention.
@ Zitrusgaertner
The tree bears stable trifoliate leaves, relatively large, i.e. larger than Poncirus trifoliata, slightly wavy. I can post pictures which show the leaves, maybe you can compare them to your 899F and 899H .