Mercedes B-Class
Pics and measuers at http://www.ridc.org.uk/5271 Really needs the version with the sliding rear seats to move forward enough for useful depth for the chair (unless a very short chair).
Model: B-Class W246
Year: 2011-2018
Style: Mini-Estate
Region: World
Measurements
Boot Depth: 836mm
Boot Opening Vertical Height: 753mm
Width at Wheelarch: 1050mm
Transfer Height: 600mm
Boot Sill height: 630mm
Boot Door Width: 1050mm
Length Of Car: 4359mm
Measured By: GE