My company published such a guidance in OM-A:
When following a standard instrument approach procedure, the altitudes prescribed in the procedures must be adhered to. Descent to the next lower altitude must only be made after passing the relevant fix and provided the aeroplane is following the track specified in the procedure.
When not following a standard instrument approach procedure and cleared for approach but not for any specific altitude (e.g. following a radar vector or a direct-to intercept the final approach track), descent to the next prescribed altitude of the procedure may only be made under following conditions:
- the flight crew has to assure terrain / obstacle clearance is safe and
- the aeroplane is established on the final approach track.
When conducting a visual approach descent below minimum flight altitudes and reduced terrain / obstacle clearance may be accepted.
In your scenario I would maintain 5000 ft until IAF and then follow the published profile.