Does this not work because I need to Groupby GoodsType.Description and TransactionType.Descriptiion and both have the same name.
Is there a away around this?
Or ... is this why you should always prefix your field names? :(

                var pBI = context.TransactionDetails.
                    GroupBy(t => new { t.Parcel.GoodsType.Description, t.TransactionHeader.TransactionType.Description }, (key, g) =>
                    new
                    {
                        Transaction = key.Description,
                        Goods = key.Description,
                        Weight = g.Select(t => t.Weight),
                        Amount = g.Select(x => x.Amount)
                    });