It is not to stop the export of meat, but only of live animals, so that they do not have to suffer long voyages, and road journeys, or slaughter in countries where animal welfare is not taken so seriously.

Besides which of course, and I am sure the government has thought of this, (Indeed it may be the real reason.) meat has a higher price tag as an export, because of course the jobs and proccessing are kept this side of the border.

Hi Fernapple, The store down the road from my house sells only British meat. We have plenty of meat (and vegetables) to go around almost to the level of self-sufficiency, plus surplus for export. It helps British farmers do well.
It is kind of ironic that Brexit gave the UK government the freedom to raise the standard of animal welfare.