Sorry, should have expanded.
All of planned departure airfields have been approved by operations, to one of 3 catergories. (A B or C ).
The take off performance data is listed for each of these, with data listed for each runway and intersection which we are permitted to use. This gives us all the normal information for temperature, flex, head or tailwind, low qnh corrections etc. At the bottom of each page is a description of what we should do in the event of engine failure, which is where I've extracted the description of what we do for LHR. This has been provided by our performance department and has taken all the airfield obstacles into account. Each airport has an obstacle chart for each runway.
Therefore in following the procedure, we are relying on our performance people to have number crunched it on our behalf.
To get a gross overview of what high bits are where, as the SID charts don't normally show terrain, then the final approach (eg ILS or VOR plates) charts, as well as a radar/terrain chart if published enables you to see if what's proposed is sensible. Hope this clears it up.