Were the Electoral Commision Expecting a Low Turnout?

Seems to be pretty chaotic in many wards, people being turned away as not enough returning officers are available to handle the number of people wanting to vote.

In Manchester hundreds have been turned away, and the BBC are reporting similar across the nation.

Looks to me like the Electoral Commission set their stall out for around a 60% turnout, and discovered quite a lot more want to vote. Which is good for democracy, not so good for my bet!