The new Tory leader takes over on July 23rd, like you said.
Two days later on June 25th, parliament goes on holiday for the summer
This is now a very interesting date.
We've had a two year parliament, so what should happen is a formal notice of prorogation is given on June 25th
If the new Tory leader gives a formal notice of prorogation on June 25th, then we know Brexit won't happen.
otherwise the Queen's speech fails and we get a general election, where at least once party offers a new referendum.
If Parliament is prorogued on July 25th, it means Brexit is over. The new Queen's speech will see to that.
No screaming, no running around, no howling. Prorogue means a Queen's speech in autumn, and no Brexit.