Although this includes a short, narrow section of Bournville Lane, which is pretty unpleasant, it does provide an otherwise quiet link through to the Stirchley Co-Op and a number of residential streets.
At this point Bournville Lane is a wide dual carriageway, with additional space for parking. As ever there is no space for cycling. Isn't it time for some remodelling? In the meantime, cyclists heading towards Bournville should make use of the zebra crossing. However, be warned that the road is so wide here that motorists often don't notice someone just starting to cross the road on the far side.
The tunnel under the railway is one-way, including for cycle traffic. Since it is very narrow, this is an ideal location to create filtered permeability by closing the road to motor traffic and making it two-way for pedestrians and cyclists.
Cycle on the footway in the access drive to Cadbury World, or the carriageway with the speed bumps? The under-used footway seems to be the better option.