Whether the company has a UK base is only half of the problem:
If the goods supplied reside across the EU border (ie. They entered the EU and crossed the duty border) then they will be then have to be imported to the UK. Duty will be applied (unless under £135). This isn't discretionary, or a matter of companies pushing paperwork in a certain way: it is absolute.
If the company has a UK base it has two options to avoid their goods crossing two borders and incurring duty twice (which is happening a lot at the moment due to many manufacturer's pan-Euro distribution arrangements):
- they can bring their goods from manufacturer direct to the UK and supply from a UK facility like other UK dealers (rather than just having an administration 'office'). This is expensive, but the way some big EU companies may go
- they can house and supply their goods from a bonded warehouse in the EU. This specific facility, whilst physically located in the EU, is notionally before the border and so not 'imported' when they enter the warehouse in the normal way. The company can therefore choose to import them to the EU, or UK, or wherever instead when they are sold.
The VAT implication is of course different, and (threshold aside), should be charged at the rate where the customer resides, and is normally applied by HMRC (via the courier) on imports. If the goods are imported over the threshold and the supplier has charged VAT, they should be able to refund this as they have exported it from the EU, and shouldn't have charged in the first place.