Just 28% of Renault Clio Mk2 and Clio Campus owners have responded to a letter from the manufacturer warning them to have their bonnet catches checked or replaced, according to the Vehicle and Operator Services Agency (VOSA).
This is despite Renault writing to more than half a million owners of the affected cars last year, saying that their bonnet catch could fail if it is improperly maintained.
The low uptake of Renault's offer of a safety check-up follows claims on the BBC's Watchdog programme that 78% of affected owners hadn't received its warning letter.
However, Renault officials say that the figure of 78% is untrustworthy as it was taken from a poll on a website set up by disgruntled Clio owners and which has less than 50 members.
Renault hasn't yet responded to our requests for a comment on news that only 28% of affected owners had taken their cars in for safety checks.
Second letter being sent
The news also comes as Renault is preparing to send a second letter by recorded delivery to about 565,000 owners of the cars affected.
Renault says it's sending the second letter because it is a responsible manufacturer committed to making sure owners of its cars are safe. It denies that a small response to the original warning letter has prompted it to take further action.
Letters will be sent by recorded delivery, although the high volume of letters being sent means that they will be posted in batches, and some owners may not be contacted for up to a month after the first batch is sent out.
A third letter on the way?
Jeff Streeting, Head of Vehicle Safety Branch at the Vehicle and Operator Services Agency (VOSA), has said that the organisation is continuing to work with Renault on the Clio bonnet catch issue, and that a third letter to car owners may be required in about a year's time.
However, he has stressed that VOSA is happy with Renault's handling of the situation so far.
'There are always concerns unless everyone who has been written to has responded,' he said. 'With a response of around 30% at present, Renault has taken the decision to send another letter, this time by recorded delivery.
'However, it would be entirely in keeping with past situations that have been similar if Renault was to write a third letter. Ideally, you want to achieve a 90% response rate, and that will usually require a third letter to be written.'
Why there hasn't been a VOSA recall
Streeting has also explained why the Clio bonnet catch issue hasn't led to a VOSA recall.
He said: 'Recalls are for design or construction issues that have catastrophic results. If you can maintain a part by normal procedures then it is not defined as a safety defect.
'VOSA experts, in conjunction with Renault, carried out a thorough investigation into reports of spontaneous bonnet openings of Renault Clio Mk2 models. This found that there was not a design or construction defect with the bonnet latching mechanism.
'Instead, it was found that inadequate maintenance - through lack of cleaning and/or lubrication - could lead to the latching mechanism failing to operate correctly. This is the reason why the issue was not the subject of a formal safety defect recall.'