Paypal Standard: Now requiring a PayPal account

My website (www.psvcircle.org.uk) uses PayPal Standard as its payment method and is currently running OpenCart 2.0.3.1.

When customers go to checkout although PayPal gives the option of Checkout as Guest on the first page, when you click it at the bottom of the page before you can continue it is now requiring customers to register a PayPal account.

I've checked our PayPal settings and these have been set to allow checkout without registration. Does anyone know why this is happening. It didn't do this previously but no changes have been made to cause this that I am aware of.

PayPal seems to keep tweaking its payment page- this is the third change we're aware of over the past few months. They've just changed it again to allow you to Register OR NOT. Hope it stays this way!