Reset restrictions passcode - HELP

I have a 2012 iPad2 which is now set up for my children, at some point a Restrictions Passcode was set up, which none of us can remember or have made a note of. Sooooo I've followed the advice of several posts on here and I backed up my device, then I restored it to factory settings. All good so far. Unfortunately now the device will not connect to the iTunes with the backup as it suddenly requires a newer version of iTunes to connect, but the iTunes will not update as the computer is too old for anything after version 11.4.

So how do I set up my iPad to work with this old iTunes and not have the original restrictions passcode?????