Been meaning to post about this all week, and I suspect that most people who need to know probably already do, but:
Penge High Street is closed southbound, more or less outside Sainsbury's, due to a collapsed sewer. The main effect on Sydenhamites, I would expect, is that the 194 bus, being a double-decker and therefore unable to pass under the railway bridges, is on a major diversion from Penge High Street, along Croydon Road, Penge, Elmers End Road and Croydon Road, Beckenham (so I am given to understand by one driver, although the TFL signs on the bus stops seem to say something different), before rejoining the route. I am told that they're going from Elmers End Green up to Beckenham War Memorial, and picking up the route again from there, although you may want to double-check that with the driver before you commit your Oyster card. In any case, the entire length of Beckenham Road is not being served by the 194 (although the 358 and 227 are covering the section between Kent House station and the War Memorial).
Fortunately, buses in the direction of Lower Sydenham aren't affected.