At the moment, when you go into Point of Sales and display Loan cars, it displays the vehicles in the default location setup in individual users GB.location
There is a new parameter which allows you to default as per POS branch(if you have multiple POS branches) or default as per Point of Sales Department.
Note:
If a location code is set on the SO.depts record it will be used first, otherwise it will look in the POS parameters.
First, you need to enable the parameter in MS>X4>Generic CRM parameters>
Tick Loan vehicle filter by department/customer

POS Department option
POS>Misc options>Department codes

POS Parameter option
Need to setup in each POS company
POS>system maintenance>POS parameter>Flags and priorities>Miscellaneous TAB

Note that this also affects when making a loan car booking within CRM, in there it will use the creating branch from the CRM customer record.
Also, When Invoicing in POS, the job will record in CRM history with the relevant dept location in POS parameters or POS Dept, not GB.user location anymore.