Where to buy multi-stemmed Amelanchier Lamarckii trees?

Does anyone know where I can buy multi stemmed Amelanchier Lamarckii trees please. I want to plant a couple in my garden and multi stemmed would be preferable over single trunk.

I live in South Yorkshire and would like to be able to go and see the trees before buying, if not then it will have to be mail order. 

Thanks.

I would look in RHS Plantfinder, see who stocks them in your area, then contact them to see who has multi-stemmed ones. 

http://apps.rhs.org.uk/rhsplantfinder/

You could alsways buy a single stem one and turn it into a multi stem, if you are prepared to wait a while We have a multi-stemmed Silver Birch. To buy it was over £100 at the time, so I got single baby one and once it was established, I prune off the stem forcing it to grow from the base. I rubbed out all but 4 of the new shoots and now we have a nice plant.

Thanks. Had a look on the RHS site but sadly nowhere loa to me. I may have to resort to mail order. Fair point regarding cutting back a single stem tree, but I think Im a little too impatient to wait that long .

Cheers