Hi, one problem in my opinion, a scan at the roadside might have pulled up a historic code not relating to the actual fault causing the breakdown. So, as you're bang on with the lack of trust with the dealer (backed up by inept UK customer service) I personally would recommend finding a local independent Volvo garage to run a diagnosis. A "diesel specialist" as a next best option, as these engines are found in Ford, Peugeots, Citroens, Mini and more... it should be easy to get someone to check it properly. Remember most Volvo specialist's will have the same diag tooling as the dealer, which on these cars is almost vital for accurate diagnosis. Keep us posted