Went to look at a Fiesta, 2004, 1.25 Zetec, for daughter. The radio / CD player appears to be in 3 sections installed in the dash panel, each about 20mm thick. My query is, if any of this went wrong, how would it be possible to replace with by a standard ISO thickness head unit, eg, Kenwood? It seems some of the dash panel would need cutting away. Any advice much appreciated, thank you.