Funding is not phase one of a project. Deciding on the project is the first phase. Then determining its feasibility follows. If there is support for the principle then a means of pursuing the objective can usually be worked out.
Sydenham Road is not classified as a trunk route. Therefore it has no obligation to carry vast amounts of traffic. That is the function of the trunk routes in the area such as the South Circular and the Bromley to London Road. When asked "where would the thousand of cars go?" I answer "Do I care?" However the figure of thousands is inaccurate.
Most peak traffic along Sydenham Road stands still for much of the time. The congested nature of the road owes itself to a blockage at each end and numerous sets of traffic lights purporting to afford pedestrian access but in practice merely switching randomly to stop to impede traffic flow. In consequence I suspect that the number of vehicles successfully travelling the length of Sydenham Road is counted in dozens rather than thousands.
Improvements to the South Circular Road were approved years ago. Then, mid-project, work stopped. No statement was made about why although the hand of 2J2S John of Westminster and Hull is likely to be the reason.
Forgetting the entire project and considering some minor improvements there is no reason why the South Circular could not carry Sydenham Road's burden with ease. Don't forget that the South Circular qualifies for massive government funding which a non-trunk route such as Sydenham Road does not.
Take Forest Hill. How many houses would have to be demolished to enable the bridge over the South Circular to be widened or alternatively for a second bridge to be created beneath the station to permit a one way system to be created? Not one. The problems of right turns would be eliminated. Forest Hill's traffic flow would improve. Yes it would disrupt rail traffic for a while, although elsewhere in the country bridges have been replaced half at a time.
Take Catford. Why does Catford need two railway stations? The one line climbs to enable it to pass over the other. Trains are infrequent. The two lines combined (a simple matter) would still be underused. A second bridge over the lower line would not be a big deal. Construct the road behind Lawrence House, as planned and for which the land was acquired and prepared... and the area between the Town Hall and Lawrence House could be reserved for buses and pedestrians only. The narrow opening alongside Catford Station could be widened at low cost.
Pedestrianise this road from Newlands Park to Mayoh Road. Re-route the 194 via Silverdale, Bishopsthorpe, Mayoh Roads and the 75 along Trewsbury Road..... The 202 divert down Newlands Park, Lennard Road, Trewsbury Road, Woodbastwick Road, Kent House Road....Sydenham Road
Funding?
Here are some clues.... Europe... Lottery.... Central Government.... LB Lewisham... local businesses who would profit considerably.
Conclusion
Sydenham Road appears to the motorist to be a short cut. Local planners and engineers have ensured nothing moves on Sydenham Road and so all it does is act as a tourniquet on traffic flow. Traffic simply stands still belching out fumes and noise. Since the road contributes little to trunk traffic's flow its removal from the equation would have little effect on trunk traffic but would enable fresh air to reappear in Sydenham.
For the trolls on here ... please keep off. For those who would like to discuss real ways to improve Sydenham please consider what I say and put forward constructive comment.