.... The lugs behind the rear wheel axle slot are captive, and need to be gently prised outwards, away from the chassis, both at the same time, while gently pressing the plastic down towards the table. (If the chassis was the correct way up, we would be lifting the rear of the plastic upwards from the chassis.) The front of the chassis slots in under the metal lampholder upright. Be careful of the brass washer that you bent out of the way, and the whole assembly lifts out.