NatWest app says £0.00 fee and some FX rate but when I compare with TransferWise, the difference is £250, which means that the "FX rate" implicitly contains the fee.
Maybe not "fraud" legally but I don't want to support such non-transparent business practices.
Yes banks charge commission (where TW usualy has a cost advantage but anyway, it's a money maker for banks and calculation of the fx rate to be used at a given moment is not something simple)
2.5% is a rather expensive fee for a GBP-EUR transfer, especially on £10,000! Some banks offer as low as 0.4% (on top of the real mid-market rate), probably even less on large transfers.
From experience with bank accounts from 4 different European countries those instant transfers definitely don't work everywhere and are often accompanied by an extra fee.
Edit: And this is 2020. I highly welcome some innovation in this field - five years ago..
Euro transfers have become instant and 24/7 thanks to the SEPA Instant Credit architecture:
https://www.europeanpaymentscouncil.eu/what-we-do/sepa-insta...
You can transfer up to 100k EUR in less than ten seconds; works overnight and during weekends and holidays.
In the UK, at least Revolut supports this already:
https://blog.revolut.com/sepa-instant-euro-transfers-now-ava...