  We present angle-resolved photoemission studies of (La1-zPrz)2-2xSr1+2xMn2O7
with x=0.4 and z=0.1,0.2 and 0.4 along with density functional theory
calculations and x-ray scattering data. Our results show that the bilayer
splitting in the ferromagnetic metallic phase of these materials is small, if
not completely absent. The charge carriers are therefore confined to a single
MnO2-layer, which in turn results in a strongly nested Fermi surface. In
addition to this, the spectral function also displays clear signatures of an
electronic ordering instability well below the Fermi level. The increase of the
corresponding interaction strength with z and its magnitude of ~400 meV make
the coupling to a bare phonon highly unlikely. Instead we conclude that
fluctuating order, involving electronic and lattice degrees of freedom, cause
the observed renormalisation of the spectral features.
