Essentially 4px are a combined logistics and distribution company.
Rather then use ems or dhl who route packages through their own hubs and often through official customs channels, 4px ship directly between their own warehouses using their own logistics infrastructure.
So your package will go from the China warehouse to the Uk warehouse, where it will then in turn repackaged or re labelled to be shipped to your country. As it looks like it’s coming from the Uk, the customs will be bypassed.
Thats my understanding anyhow.
Its not necessary to use their own WH per say, its mostly in the documentation. 4PX will have a service contract with DHL at half what you & I pay. It's less expensive for 4PX to use exciting DHL set up rather than buying their own.
When our TD ships from China they book with 4PX.
Shipper: Puretime
Cnee : Nipe
4PX than creates their own Master bill of lading
Shipper: 4PX China
Cnee: 4PX UK
4PX than books the shipment with DHL at lower rates.
Once the package arrives at DHL UK (or another WH ) its picked up by a third party and shipped off to Germany based on new labels / documentation if that's where Nipe lives. DHL might not be involved in this leg.
German customs will think the good are coming from the EU.