It seems there have been a number of places where people have been unable to vote yesterday. There have also been some stories of problems with postal ballot papers not showing up. We've been affected in my household. When my wife realised she would be away on business on polling day she applied for me to act as her proxy. She posted the application 1st class on the Thursday when the deadline was the following Tuesday. We subsequently received notification this week that the application was received too late. I suspect that it was delivered by Royal Mail before the deadline, but that due to the volume of applications close to the deadline, it was not actually processed until afterwards. Unfortunately I have no way to prove this, as the form was not sent by recorded mail, but it would be a rare letter that did not manage to travel barely half the width of the city in 4 postal days.
After several successive elections where we've heard much concerned comment about voter apathy and low turnouts, it does seem rather unfortunate that a 100% effort has not been put in to allow those who wish to cast their vote to do so.