Sacha,
Haven't seen the plant at the Garden House.

Some offerings
Acer palmateum karasugawa some leaves all pink, some variagated
http://www.hippopottering.com/karasugawa.html

Acer negundo 'Flamingo' has pink juvenille leave thought. I understood
that this was a green leaf, but gogling I found pictures showing it to
be variagated

Clifford
Bawtry, Doncaster, South Yorkshire