G-RICH
FTOs can use any "approved" training material. This material forms part of the approval process.
Several of the ground school providers supply/sell their material to other FTOs, mainly overseas. It is a BIG source of revenue and I suspect without it, 1. the cost of course to in house students would be much larger and 2. some of them might be financially struggling.
DeanM7
If you have not already, I should go and pay a visit to any of your potential schools, inspect their classrooms, notes (not quite so critical for full time), talk to other students and generally get a feel for the place.
When I did a full-time course many years ago at ATA Coventry this was near my home and therefore no accommodation costs, something you need to factor in.