Voting Fraud in Bradford

The BBC are reporting that seven men have been charged with voting fraud in Bradford relating to the last General Election.

This makes me want to ask two questions.

1) Are they politically involved in any way ? If so, the political party in question needs to throw them out of their party, should they be found guilty.

2) Why has it taken 2 and a half years for the police to investigate this ? Isn't it about time the police had a national unit who are trained and understand electoral law so these things can be swiftly dealt with.