For ERC-20 transfers initiated by MetaMask the TrustVault iOS app shows the incorrect fiat price. For TrustVault supported assets it will show the current ETH price (~2,800 GBP), for other tokens it will show a price of 0 GBP. If your app is set to a different currency the values will be shown in that currency.
We are currently looking into a fix for this issue. You can be assured that your transfers will be correct, this is simply a display issue.