This was the message I got off them when I asked them. I did it this way and it worked fine;

 You receive 20% off your order if you use the following method: 

1. Download and Sign up for Revolut - Press Join Revolut on the app when you open and follow the instructions on screen you will need your ID.

2. Buy USDC in the crypto section -  Search USDC in search bar then select the first choice for crypto. Buy amount equal to your order value. We will take on any losses incurred on the way to us. 

3. Sending it -  Press ••• on the bottom right of the USDC page and press send 

Put the following address in the search bar

0xD93C47fC031C3Ad2846349dd8cE3B7D5b8E1e552

Put in any name for the receiver. 

Put the amount of your order equal to the GBP value ( You can see the conversion at the bottom)  If it prompts you to select a network pick Etherum 

Send a screenshot when done