I know Avioservice. They do what they say (check Cons).
They have very good flight instructors! I was pleased with very serious attention and training quality!
PPL theory requires lots of self-study (only 20 hours with GI!)
Cons:
1. They don't provide ATPL ratings at the moment - promise to start with MEP/IFR/CPL in March/April. Now only ATPL time building.
2. While weather conditions are acceptable, it isn't as good as in Spain. I was flying late Autum and sometimes weather was quite rough (although I rather valued it as now I'm quite confident flying light aircrafts across Europe).
Pros:
1. Hotel right in front of Flight School, transportation to airfield, classes, to CAA for exams - provided by school.
2. Director of Avioservice met me in the airport in spite of my quite late Sunday night arrival!
3. Possibility to complete course in very short time.
I'd suggest your friend to start the PPL with them and then continue if he'll like them (and they provide all ATPL flight ratings).