I also live in Hertfordshire, just inside the M25. I fly out of Henlow and I can get there reliably in 35 minutes. Traffic permitting.
I learn to fly there and have had a very good experience. I could go to Elstree as I can get there on my bicycle in less than 20 minutes, but I stay at Henlow.
The facilities have recently improved and the instruction is good. A great deal of different people learnt there and continue to do so. The instructors are a great mix of characters from young dedicated instructors who have never done anything else to retired airline pilots.
The grass is well looked after and the place rarely closes because of flooding of the strips. The aircraft are well maintained locally and whilst not beauty queens they do the job.