Just had a call from Craig (assistant manager in the Watford store) who said that head office have authorised me to get a replacement, happy days. Only issue is that they are out of stock, they are looking at getting a handset moved from Harrow to Watford and they'll call me when it's in. Glad I got the right result in the end, just wish I wouldn't have to have escalated it to CEO office.
Due to the integrity of the rear screen being lost due to the broken glass, the phone feels a lot more fragile in my pocket and I'm sure the fractures along the glass are getting worse.