Would disagree with the comment re Firecrest.
They were my third flying outfit, so I have yardsticks to compare them to. I had no issues with aircraft availability as a student and was certainly not aware of any kind of history of accidents during lessons.
Whilst they are not as smart as Cabair, I've found the quality of instruction to be good - they got me through my PPL just fine.
When switching my instruction to Elstree I considered Cabair but could not justify the huge difference in cost. I'm sure they are a good outfit to train with, I'm just not convinced that you need to pay through the nose for it.