Billing HMRC direct?

Someone mentioned recently they had billed HMRC direct for wasting there time rather then going through the old routine of billing a client, collecting a cheque and the client applying for reimbursement. Please could they post here or PM me exactly how they approached HMRC to do this.

I have just had a revision to a 2010-11 tax calculation to collect £1k that had already been collected in 2009-10 'Because the underpayment was in the tax code for 2010-11' As though the bl**dy tax codes were infallible and we just made up numbers on the tax return. 

I am still angry.