But in recent weeks Hemming has been highly critical of HMRC over its handling of the confusion that surrounds the VAT treatment of direct mail.
Negotiations on the matter go back to 2012: HMRC says there has been no change to its rules, but the CTG argues that previous guidance was unclear. Last year the CTG, along with the Direct Marketing Association, asked for assurances on both the future treatment of bulk mailings and the possibility that HMRC would bill charities retrospectively. This, said the CTG, might have cost some charities hundreds of thousands of pounds.
In December, HMRC said it would issue new guidance providing greater clarity and that it expected direct mail suppliers to apply the guidance by 1 April. On 30 March, the CTG complained that this guidance had not been issued, and Hemming denounced HMRC's "failure to publish updated guidance" as an "unacceptable situation".
In mid-April, the CTG published letters from HMRC to give members some understanding of the revenue's position - in a press release, Hemming again called the situation "unsatisfactory". He also expressed disappointment at the revenue's communication strategy: "HMRC should not seek to establish policy by means of letters to representative bodies and then expect these bodies to publish HMRC guidance - official HMRC communication channels should be used to disseminate policy."
Hemming says he accepts that the purdah restrictions on the civil service make it difficult for HMRC to act decisively right now, although the CTG remains hopeful of progress. "We fully support the revenue in achieving its objectives to protect the public's money, so we're not pushing for anything other than some sort of clarity," he says. "All we're interested in is getting all the information we can out to our members. The last thing we want to do is damage any relationship we have with the revenue; that would be crazy on our part."