The handover pack should include the following information once the solar PV system has been completed, commissioned and MCS certificate issued.

MCS Certificate.
Invoice.
FIT application.
Energy Performance Certificate (EPC).
Roof Calculation for snow and wind loadings.
Copy of circuit diagram which includes the inverter settings.
Solar panel data sheet.
Solar panel serial numbers
DC Test results and panel tests.
A declaration that the system complies with current regulations
Electrical Installation certificate
All manufacturers brochures, etc.
WORKMANSHIP WARRANTY
RECC Installer feedback form.
Other items that will arrive in the post from your Local Building Control.

If you don’t receive all the above paperwork don’t pay for the system until you do get them.

If your MCS installer is an NICEIC installer, use their online certificate checker to make sure they have registered the work which they have done.

There are good installers out there you just need to find them and here is the best place to start.