Neff is only a Built-In Product brand. They do not make "freestanding" products. They are part of the bsh group which manufacture the brands as mentioned by previous poster.
Neff are a strong brand in the UK in Built In. Hotpoint are also a strong brand but bot so much in integrated products. Hotpoint is now owned by the indesit group (Ariston). Hotpoint products in the built in sector are trying to build on the success of the hotpoint Uk brand strong in homelaundry. Their products are not anywhere near as good as Neff or BSH group. I say this from knowledge in the indusrty as well as personal experience with "indesit group" products.
The one thing you can be sure of though. A built under double oven are basically a UK product. Europe and most of the world do not really use double ovens. Us Brits LOVE to Grill. So all built under double ovens from all manufactiures are made in the UK.
Do me a favour! Dont buy Hotpoint. and you'll be allright