Well-spotted!

It is possible to have a text customized for UK and still use euros (for example, when referring to the original cost of something), so I do not consider using the euro sign as an example necessarily doing it wrong. Using the same amount and currency in this example makes it easier to scan, which was my goal here.

But it is a sharp remark, and I agree that translating the value into the local currency (accounting for inflation if needed) is generally a wise thing to do.