Interesting. I got my information from calling the tax authorities and ask, but I'm based in the Netherlands so their guidance may be different from that in the UK.
Doesn't the Netherlands use the Euro? If so, then I think the information we have been given is consistent. For you, the MSI currency would be Euro, while for me in the UK, it would be GBP. Each of us would pay any tax due to foreign tax authorities via our own country's MOSS in our local currency, but if we charged a customer in a different currency then we would have to convert it in one of the two ways I mentioned before.