I've had a couple of things from Germany, via Amazon in the last year and no problem on both occasions. In both cases it was clear where the item was being sent from.

With Amazon and eBay, the location of the item is usually indicated at the point of sale. Some items though are marked as USA but might be shipped via warehouses in the EU (VAT?), with perhaps a seller disclaimer attached for any duties applicable to the customer on delivery.

If the item is sent via US DHL Global and then the UK part by Yodel, you could receive the item within 3/5 days?.

Word of warning, if the item is delivered by Yodel (which is very likely with DHL Global). It could be delivered at anytime, including evenings, and the parcel left anywhere looking 'safe'. Items can be left out in the rain, so hopefully the item will arrive in a plastic bag mailer for protection. Some delivery people will leave items with neighbours, but a card in the door should tell you this!.

I have regular deliveries via Yodel, and they use quite a number of part time sub-contractors with own cars/vans/taxis.

For Transatlantic or European that requires international paperwork completion. I find UPS quite good, including tracking.