Changing date of first registration

Morning all,

One of my NT's MOTed a jersey plated car yesterday which failed. The customer didn't bring any documentation in and as he is a regular, he looked up the vin number for the date of first use but it turns out he used the build date and now the customer would like it changed as the date of first use is a year later.

Is this a call to local office or can we change it on the retest?