"As for knowing when your ready, at some point you'll find yourself going downwind and saying "ho Hum this is taking a while" you've nailed your height, trimmed and are on approach speed and finished your checks."
I've just revisited this thread having taken back to the air after taking (involuntary) time out from training. I've put in some intensive time to catch up and I'm finally at the "Ho Hum" place mentioned above. I've stuck with 2 instructors all the way and I'm almost ready for solo. Loving every second of it apart from the occasional "Go Around" due to due dodgy crosswind approaches. I'm very happy with my chosen instructors, they push my limits without getting me overwhelmed. Incidentally I'm training in EICK where ( it seems) crosswinds are a way of life.