Heading south along Denmark Hill/Herne Hill you can’t trun right into Herne Hill rd, nor can you turn right into Milkwood rd. Heading south west along Coldharbour Lane just past Loughborough Junction if you turn left into Hinton rd heading for Milkwood rd you are confronted by a 12’3" bridge.
I can get you in there but I can’t get you out again because of this sign on Coldharbour Lane which seems to indicate that the bridge is over 16’ one way and 15’3" the other. I suppose you could get your company to phone Railtrack/ Network Rail to enquire.
google.com/maps/@51.4661672 … 384!8i8192
There is a possible route but it is a considerable distance through a 7.5t ban with what looks like a turn you will be unable to make.