Hi Marcus,
I spent 4 weeks in Salamanca last month taking Spanish Immersion lessons at Tia Tula. I had taken about 12 classes of Spanish this winter and they put me into an already started A1+ class which ended up being fine. I inadvertently booked my departure day for the final exam day so I was able to complete the course and I'm now a A2 level student! The classes were 4 hours a day with a half hour break between. The school was fairly small but situated in a newly renovated building just 1 street north of the cathedral with a great comfortable coffee shop next door that seemingly all us students would go to during our break. Class sizes can range from 2-10 students, depending on demand and can change weekly as some students are there for just a week or two, some for several months. There's also an option to add an extra hour of conversation to your day (on a weekly basis). I did this one week as I felt I needed more practise with my conversation. Sometimes I wished I had bought this option for every week, sometimes I knew my poor old brain was so tired at the end of 4 hours that I was glad I didn't have any extra studies! I really liked my teachers, especially my morning instructor (you change professors for the afternoon session).
The school fee was very reasonable I felt, almost half of what the University of Salamanca was charging, and I thought it was good value. In fact, they had a special when I was there, pay for 3 weeks and get the 4th free. I booked my accommodation through them as well - a shared apartment. They also have home stays, where you stay with a local family. There's pro's and con's to both arrangements.
Let me know if you have any specific questions!
Allison