Looks like 3 months is too short. Cameron looks like he has no intention of getting the party started before his replacement is chosen, and that won't happen 'til October...
Ironically, it's the EU that seems impatient to get this over with.
There is absolutely no way that the British parliament is not going to ratify this. The bigger question is how this can be implemented. This is unexplored territory, for all involved parties.
Ha! Let's remind each other about this conversation in 3 months and review our arguments.