Hi Paul,
I have sent you an email where I have included the BAA Office who manage the donations.
At present we use Square to take donations. The same service we use for the BAA shop and telephone payments. I have tested the donation page just now and it was working on Chrome, Firefox, MS Edge and Safari, running on Windows 11 and macOS Ventura. I wonder if it was a temporary glitch or whether something in your browser might be blocking the Square site, link below.
https://checkout.square.site/merchant/MLW65481JK36P/checkout/SL5VCCR2YENEZGEKFZPD6AGH
Best wishes,
Andy
British Astronomical Association
Supporting amateur astronomers since 1890