Not just Pietersen.
Over four test matches, they batted seven times, and only scored two centuries and eleven half centuries.
Strauss got only one half century, and was out for single figure scores three times in the series. Trott also scored over 50 only once.
Proir scored over 50 twice but was out for less than ten on three or four occasions, if I remember correctly. Bell was out for single scores three innings out of seven, despite some verygood scores in other tests.
Their batting is weak in general.