Re:
 

Nestle has been making and selling a few General Mills cereals in Europe for about 15 years now. The deal started in the early 90s, when my wife was employed by General Mills. It was never clear just who was playing who. Was General Mills exploiting Nestle and getting a foothold in the European market? Was Nestle plotting to take over General Mills and increase its American market position?

In any case, the projected demand for cereal in Europe never happened, and General Mills bought Pillsbury and became in effect too large to be taken over. What's left is a legacy contract, pretty similar to the way Hershey has the U.S. rights to Nestle's Kit Kat bar.

The contract as it read back in the day was pretty clear that the Nestle versions were to be "substantially identical" to those of the General Mills versions. Nestle and General Mills went to great lengths to source similar ingredients and establish similar manufacturing processes. There were some new localized cereals introduced with flavor profiles more European-friendly, but I'm sure those cereals are long dead.

I would guess those constraints are still in place, so go ahead and buy the cheaper Nestle Cheerios.

If the regular variety in the US taste like cardboard, then they are ! :D

Re:
 

Getting off my duff long enough to research the topic, it appears that Nestle doesn't sell the regular Cheerios in Europe. They sell Honey Nut Cheerios, their version of regular Cheerios (which appears to be the same as Multigrain Cheerios in the US), and something called Oat Cheerios. At first blush, this looks like regular Cheerios, but the ingredient list reveal a lot more sugar than what you get in regular US Cheerios.

I will agree that the stuff tastes like cardboard packing material.

Not for whole Europe. In Germany our "Cherrios" are called "Honey Loops" and are manufactured by Kellogg.

Look for a generic brand of "oat ring cereal." You might like it better than the brand name stuff.

If you are in an area with a large US presence, such as a military base or consul/embassy, find someone and make them your new buddy. Ask them to shop in the commissary for you; not the whole shopping list, just those 'must-have' items you can't get on the local economy. It is technically red zone to buy for someone else, especially cigarettes and alcoholic beverages, but the occasional box of cereal would not be a big deal.

You can also contact the overseas division of the manufacturer and find out where to get the items. I used to go up to Bonn and met the suits at General Mills and Proctor and Gamble who ran the show up there. The Canadian Embassy folks always threw real nice parties and I worked with the Embassy Schools Sports Program and had an open invite to their place. Real nice folks.

UK vs USA
 

There’s also something else to keep in mind, the UK version of Cheerios are NOT made in a nut-free environment whereas the USA version is. My friend who has a nut allergy cannot have the UK version of them so has to go without.