Hi Andrew,
I am a great fan of the Shogun and the 2.5 would have no problems towing 1250kg as it has a max tow of about 2500!
In good condition these cars are superb but after 14 winters all will be showing their age - look for rust everywhere underneath, smoky engines, slick change in the gearbox, signs of overheating, evidence of offroading and evidence of correct servicing
They have a TD engine with two drive belts - one for the camshaft and one for the balancer - make sure these have been changed at the correct interval.
Unless you can be sure about all of the above and the car is in excellent condition walk away. Repair costs can easily exceed the price of the car in cases of rust or failure of major items.