In short it’s generally viewed as safer to use the shipping line that transported your goods to UK for haulage.  Why?  Well they own the container your goods are in, and so any error by their driver that results in damage to the container or a late return to the quay of the empty container after delivery would be for them to absorb.  However, if you request merchant (independent haulage) then their responsibility would end and yours would begin as they have handed their container into your charge when the error occurred.  In such a case, you would have to pay any fine or repair costs (or hopefully your merchant haulier would absorb this through their own insurance).

Also if you use merchant haulage you often have to pay the shipping line a handover fee (often around £70) and this is often called a LoLo fee.  They have the right to charge this anyway as it is a fee for taking the container off the vessel but it is usually waivered if you let them delivery the container for you.

That said merchant haulage can be cheaper on shorter journeys from the port (arguably 100 miles or less) and they are a great asset at bank holidays when shipping lines often get short of drivers, especially in the run up to Christmas.

The further away you get from the port of collection the more economical ‘grid’ delivery (used to refer to shipping line arrange haulage) can be.