not sure if the RTA is like the QT up here but you can request QT here to contact the owner and have them contact you if they wish to.
the roof dent - not that bad. mind you to fix it will take a full strip/spray of the roof. mine has one like that on teh opposite corner same colour.
rest of it decent nick and definitely worth doing if you can get you hands on it.
as for opening one. easily done with the correct tools.