From what I hear of Cabair at Elstree:
Good instructors, aircraft for PPL training are almost new PA28s and availability problems are rare. A Katana is supposed to be arriving shortly.
But, Elstree is very crowded, especially now one of the taxiways is waterlogged so there is lots of backtracking going on. Expect plenty of go-rounds due to runway occupation or conflicting traffic. (Not Cabair's fault of course.)
And all for £150 per hour! Plus landings!