Posted: 16/05/2014 at 16:00
Pyracantha is quite commonly grown against a wall or a fence, and in fact is recommended for such a purpose by the RHS. http://www.rhs.org.uk/advice/profile?PID=431
They do advise that it should be planted 50cm out from the base of the fence, but that is to avoid the roots being in the dry 'rain shadow' that is always caused by a fence or wall, and is nothing to do with the possibility of damage to the fence. I know of several planted much closer that 50cm.
In fact planting the shrub close to the fence may cause it to grow less vigorously.
I really don't think that the pyracantha is any cause for concern.