I think with APR you have to pay an additional £150 to have the ability to switch to stock. Whether the previous owner paid that, who knows. Maybe google how the APR switching works and try it on yours? Usually it's a combination of key on, key off, key on, press gas pedal to the floor and up on the left stalk. The rev counter needle will move to 1000rpm for map 1, 2000rpm for map 2, 3000rpm for map 3 and so on.
The thing is though, the stock map won't be the actual factory map, it will be a 'stock like' map which is broadly similar to factory, but not exactly the same. The reason for that is on these cars, you can only go forwards with the maps, not backwards. The factory map will have been overwritten by APR's software and therefore a copy of a stockish map will be held in memory somewhere. You can't get a factory map from anywhere other than main dealers, and obviously tuning company X, Y, Z can't ring up VW and ask for a copy of the map.
If you're into learning about the car, then it might help to explain how the software and coding works. See, Apple learned from VAG in locking hardware down to software keys. The only way you can get software onto things like engine, gearbox and steering ECUs is to connect the car up to VW's servers. It then reads the VIN and downloads the specific software for that module. You cannot pick and choose what you want, for example, the engine map from an S3, or the steering profile from a Passat etc etc. It's all tied down to the VIN.
Revo keep a copy of a stock like map in memory, but you have to pay £120 for an OBD2 switch box to change over to it.
You'll just have to teach your other half to be gentle with the gas pedal in bad weather
