Hi,
Just to warn you that in general the Portuguese are not big on turnout, so you may have to be a bit flexible with regards to the type/amount of turnout available - many yards will only be able to offer limited turnout in the form of sand/dirt paddocks. On the plus side it's quite common to have stables/shelters within individual paddocks so that the horses can go in and out as they please.
I've asked some friends and they have told me of a few yards for you to look into.
Centro Hipico Dom Carlos (Cascais again) - no website that I can find but if you google it there's a few links with their address and phone number.
The other is the Academia do Cavalo, in Vila Franca de Xira - this has been mentioned to me with the following recommendation -
"It's not expensive, it is run by a highly experienced and responsible person and I have peace of mind knowing that all my horses are getting the best of care AND my instructions are carried out. I'd be willing to speak to your friend and to show her around."
Only just found this forum! We're in Tomar, about an hour north of Lisbon and can offer 24/7 turn out either on our paddock paradise or in a separate paddock with lots of shade. We're putting in a 20 x 40 sand school (starts next week - yay!) and have a 16m round pen, a wash down area and three big boxes