Re: GT JTD that will not start
The 16V multijet in the GT has been around lin one version or another for long enough for any service dept worth it's salt to know it inside out so I'm a bit surprised an Alfa main dealer can't fix it (assuming they actually have an in-house service dept).
I think the biggest difference with the GT engine over the previous incarnations is the Bosch ECD16 management system which is fairly new and only used by Alfa in the GT and Crosswagon as far as I know. My best guess is that they haven't enough experience with the ECD16 yet to figure it out which is why they are asking Alfa GB who hopefully have a red batphone linked to Bosch.
My totally non-expert, know-nothing opinion is its the engine management system playing up. That or you've filled it with unleaded.....