This on eBay
https://www.ebay.co.uk/itm/Volvo-240...IAAOSwsA5a6YKP might be the extra sturdy type of tow bar that I think I remember Clifford Pope mentioning. It has an additional centre fixing. As I recall, Clifford said that coped much better with seriously heavy loads to tow.
Seller says from a saloon. With that centre fixing, the estate might need a different version?