Hi ,Firstly is your caravan alluminium or fibreglass. Products do differ for these differant surfaces .On ally i`ve allways used CRC products the last few years ,There`s cut and polish which is harsher and will cut through a paint coat ,and Polish and wax .Allways have a go with the least abrasive first . I`ve allways applied by hand ,(much more control for only applying with as much pressure as needed) ,doing a small section at a time . Yes by all means get an electric buffer as they do save some serious elbow work for finishing the polishing off but lightly does it as these too can `burn` the paintwork if pressed too hard . Andy .