I did a quick search of all the NPC web sites and here is a list of GLOs with an European alumnae chapter. Note that not all GLOs had their alumnae chapters listed on their web site. (i.e. Kappa Kappa Gamma's was under construction.)
Alpha Phi - Overseas London (Colonizing Chapter)
Delta Delta Delta - United Kingdom
Delta Gamma - UK London Alumnae Association
http://www.geocities.com/londondg/
Pi Beta Phi - London Pocket
Sigma Sigma Sigma - United Kingdom