This HGV is typical and he makes 20 drops of the wheeled baskets you can see ( folded) on the tail gate, and this can take 8-13 hours.
The economics of trams means that a single tram unit with maybe 300 person capacity, will be full at rush hour, but more or less empty at other times, but they will still operate the same tram unit because the marginal cost is very low, unlike with a bus.
So HGVs can easily transship these wheeled baskets at any out of town tram stop, on the convenient side of the city ( not a special facility in Bristol) for onward shipping to Bath, using electronic tagging and locking to prevent theft.
A back of the envelope calculation shows this would be wildly economic for the freight company, even costing in the cost of council freight Marshals to take over onward delivery. ( note Bath already has these Marshals. )
The previous tram system used to have a thriving trade in delivering parcel and even timber and beds.