And if you want the cards stacked in your favour always book the slot just before lunch and give your instructor a can of Juice to drink just before you leave.
There is no rush to go solo. Huge swaft of the paint brush here but I found those that went solo quickly had to spend longer at nav and those that took a bit of time to go solo took less time at the nav. I don't know if it was the additional practise at RT, being more used to being in the air or the old differnet side of the brain thing.
If it does get to the stage though of 3-4 lessons with no improvment or the instructor finding excuses not to send you. Have a word with the CFI, its maybe time for a fresh look at you and someone elses tactics.
I found at the beginning working as a FI i was looking for perfection. Towards the end I was looking for 3 circuits without me having to patter, and the biggest tick was the gut feel the student was ready. And I was never into the huge briefs before first solo (I was very doudtful if any student would remember any brief after being told they were going solo) after checking previously there medical was in, it was "1 circuit see you back at the school" get out and not look back.
MJ