I've now got a stainless exhaust on my GLT so these are surplus to requirements. The backbox is made by Bosal (part number 283-933) and can be fitted to either a hatchback or saloon - it's also no longer available and one of the better remaining OEM replacement sections. The middle section is of unknown make and in all honesty doesn't fit perfectly, though could be modified to do so - the pipe exists out of the silencer at slightly the wrong.
£30 for the rear, £20 for the centre... collection from Coventry.