I've always had estates for towing, it all depends on the OP's budget. Years ago I had a 2002 Mondeo TDCi estate (manual) - brilliant tow car but had reliability issues regarding starting/fuel injectors. Replaced with a new Passat 2.0TDi estate (manual) in 2006 - reliability issues again with injectors but I understand the later Passat's are a lot better. After that I had a couple of manual Mercedes C class estates with the 2.1 diesel engines, nice cars but the parking brake was awful.