By Charlie Conchie A Labour parliamentary candidate is facing questions over his past business career today after the FX firm he founded collapsed and left customers millions of pounds out of pocket. RationalFX, which was founded in 2005 by Rajesh Agrawal, who is the Labour candidate for Leicester East and former deputy mayor of London for business, claimed to have handled over $12bn worth of international payments before it folded into administration late last year. The Canary Wharf-headquartered outfit shuttered its customers’ accounts and blocked them from withdrawing cash before calling in…