Hello and welcome to the forum Richard.

Im glad you have decided to buy a Fiesta they are great cars as everyone will tell you. You have come to the right place to ask questions m8.

To get around the Ford Standard Unit problem. An aftermarket dash fitment would need to be purchased, im sure some of the Mk6 owners would enlighten you on this. With this fitment the old sterio could be taken out and the new dash fitment added so that the space is right for a standard rectangle head unit to be slotted in.

Ill try and find a picture of this to illistrate what i mean.

Im always down your way as im always down in Portsmouth due to having a house there.

You may recognise these pictures then