Only send the currency that matches the account. If you send a currency that is different to the account, you could be charged more or it may not arrive.
For example, if we receive a Euro payment into your GBP account, we'll have to convert the Euros using our daily exchange rate and add 2%.
If we receive a US dollar payment into your GBP account, it will not be processed and will be returned to the payee.
You can only receive USD into your US dollar account, and Euros into your Euro account. Any other currency (including GBP) will not be processed and will instead be returned to the payee.