Grenville Turner said employees within Countrywide’s stable of national estate agents must not “misunderstand” their job of assessing the affordability of potential purchasers by asking for decisions in principle as a “condition” for putting offers forward.
Mr Turner said it had proved necessary to “reinforce” guidelines as certain issues with estate agents’ behaviour had been “highlighted in the marketplace” recently.
He said: “It is up to us to keep reinforcing guidelines in the light of recent claims from brokers and that our members never misunderstand the rules over what is and is not right.
“It is good business practice, and it is not enough to say that our estate agents are whiter-than-white - we have to prove they are demonstrably whiter-than-white.”
Mr Turner said Countrywide had long supported tougher regulation for the sector but would not be drawn into the debate about whether the government should have transferred regulatory powers to Powys County Council.
Mr Turner will leave his role following a tumultuous period for Countrywide, which was re-listed on the London Stock Exchange in March last year.
Neville Richardson resigned as a non-executive director in the run-up to the initial public offering amid criticism of his role in the doomed merger between the Britannia Building Society and the Co-operative Bank in 2009. Robert Davies also stepped down as non-executive director for personal reasons.
Mr Turner, who will become a non-executive chairman at Countrywide, said it was the right time to hire someone new to oversee “further changes” to the senior team in the next five years.
Countrywide’s 2013 financial results showed that total income rose by 11 per cent to £584.8m and earnings before interest, taxes, depreciation and amortisation increased by 37 per cent to £86.6m.