Weathergirly, there is only one DME at Dundee, so D8 can only refer to that (i.e at the airfield). If the approach had been flown with sole reference to ground based aids - for which the approach plate is written - then the only ranges a DME could display would be the correct ones. The problem was essentially that there was a mix of GPS and ground based aids in use. The approach plate was not written for that.
What you also need to consider is that thousands of pilots over the years have flown that approach and not come to grief; it is not that approach that was at fault.
There is perhaps a deeper issue here - that of the widespread use of GPS but no requirement to be trained in its use - but that is not an approach design issue.