Where can I purchase a Grafted Avocado plant?

Does anyone know where I could buy one in Ireland, please, i.e. scion from a proven fruiting tree, grafted to root stock? I'd also be interested in the scions ungrafted, so that I could graft them myself.

I've had success overwintering plants grown from seed outdoors, including some that took root when I spread compost (seeds had been left in compost and I hadn't intended on planting them). I'm aware that these may never fruit, and if they d,o it will take a long time and fruit yields will be low, therefore, I'd like to plant some grafted plants.