It appears fundamentally to be someone's private collection of old cars and motrobikes that they let the public see. It's not a formal museum in that sense. I thought it was a little pricey at £7 each for adults too to walk through three sheds of cars but as the kids were let in free (not sure they were supposed to be) I've no complaint at the overall price. They were also allowed to get in and on some of the exhibits and get their photos taken and they loved that.
Friendly host who was happy to chat and some genuinely interesting exhibits. Not sure how easily I'd actually have found the place without satnav but it's certainly worth a visit if you or your kids are interested in old cars.