Except the bus never actually said we'd be giving £350m per week to the NHS. It said "We send the EU £350m a week - let's fund our NHS instead." Nobody in their right mind would assume that means we'd just divert all that money to the NHS, nor is that a decision that the Leave campaigners can make - it's simply a statement that the NHS is grossly underfunded while we send billions of pounds a year across the channel.