I have been working my way through the Stories and had reached series 5.
Today I logged on and my level was shown as level 9 Stories - way beyond my skills at the mo'. Anybody know if it is possible to 'reset' this level, please?
You can't reset, but you can just go back to where you are comfortable and continue from there - you can do the stories as often as you like.
Make sure no-one else has logged into your account and / or used it themselves - do you leave it logged in on a shared device? Avoid that!