I always found the civil servant Sir Michael Franklin to be helpful when I was European correspondent of Farmers Weekly in the 1980s. His knowledge of the affairs of what was then the EEC was second to none.
He was always patient enough to wait awhile when I asked him any questions about ministerial meetings. Although he was always discreet and would, understandably, press home the government line, he gave the impression that it was best to answer as straightforwardly as he could in order to help journalists such as myself know which way the wind was blowing during negotiations.