It's symbolic (or obsessive) in some ways, but I think London is a bit different to round here.
I'm actually struggling to find places to campaign, without driving miles. In this election, it's likely to be further out into Lancashire.
In London they can easily be overwhelmed with activists. At past elections, they've had seats with many thousands padding around on election day. I remember seeing messages telling people NOT to come and campaign in some marginals. Labour are probably grateful that they've got another fight on their hands to keep a few of them busy :)