Hello Annie
About a year ago we had a dent in the side about 50mm in dia about 5mm deep we took it to 'Caravan Medic' we had a little troble with the local one (didn't seem interested) however we found one in Swadlicote in Derbyshire he did it in the same day and I defy anyone to discover where the dent was when he had finished, cost about £40-50, hope this helps