legal towing

hi , im wanting to buy a caravan for me and my wife and my dog so we can start having holidays together alone now our children are grown up.the only problem that i have i dont really know much about caravaning.i didnt pass my driving test untill 1997 and was told i have to have the proper licience to tow caravans.i went to a caravan sales to enquire about caravans and towing.i was told that i didnt need to get a new licience for towing if the caravan weight was less than the max towing weight of my car.i have a xtype jaguar 2.0d classic.can anyone help me and give me advise.thanks martin.x