Items to check:
Heater hose. We have replacements. £40.00?
Heater Valve. We have replacements. £150.00
Radiator fan. Resistors (Mk1??) We can replace.
Water ingress in footwells.
Water ingress in the boot. DVD/SatNav player area?
Water tubes from the Sunshine roof (if fitted)
Heated rear screen elements.
There should be a full under engine plastic tray.
Washer bottle cracks.
Some cars have one horn some have two.
Rear centre seat belt can jam.
Sometimes? there is a mustang emblem on the throtle body.
The best car I have had of over 50