The difference between being a Scout leader and being a teacher is that in scouting, you have some say in who is in your group. You generally have more supportive parents to start with (the feckless don't send their kids to Scouts), you can exclude those who do not pay (as a teacher you have to teach those without equipment all the time), you can exclude those who repeatedly affect the fun of others in the group. You have helpers, and parent helpers. You even have a say in the activities you do. None of that applies in teaching, where you get what you are given, will see those who verbally abuse you and destroy your lessons day after day back in the classroom and have to more or less suck up willful destruction of property along the way, usually all while being left on your own.
The difference between being semi-senior in your job with what sounds like managerial duties and being a classroom teacher is that as the latter, you have no say in how anything is run. You will start at the bottom. From top to bottom, here is where your opinion is in the grand scheme of things: MAT CEO > MAT Leads > Headteacher > Deputy headteachers > Assistant heads > Heads of faculty and Lead Practitioners > Seconds in department > experienced teachers > you.
You will not determine what you teach, and when you teach. You will not determine who you work with. You will have no say in when you get a break, when you complete certain paperwork, when you have meetings. You will have no say in who you teach. In some schools, you get a script to use in how to speak to students. In some schools, you get a premade PowerPoint you are not allowed to deviate from (and will be expected to create more of the same for others).
You will be expected to plan, prepare and assess mostly in your own time. You will be expected to look out for, document and report on everything, including medical issues, SEN needs, allergies, mobile phone use, social media use, social issues and interactions, abuse, neglect, sensory needs. You will need to be in constant contact with parents in your own time - via meetings, phone calls, parents evenings, email. You will be expected to set and stay on top of homework, create and maintain displays, keep your classroom tidy, keep folders with evidence for all manner of things. You get 2.5 hours a week to do this in school. In addition, you will be expected to attend weekly training - twice a week while you are an ECT - after a full day of teaching and duties, to then continue planning and marking.
To the PP who said it's one year, not two - most schools are so cash-strapped these days they will not progress ECTs after year 1, but instead wait the full two years. Yes, the 30k may now have increased to 32k. It's not a lot of money after deductions for the amount of work involved.