for something with a many million pound budget, I bet I could quite effectively cache-proxy their CMS with a budget of $20,000 and four high powered 1U servers

for something with a many million pound budget, I bet I could quite effectively cache-proxy their CMS with a budget of $20,000 and four high powered 1U servers running a very vanilla nginx https setup. Probably fast enough to serve >50Gbps of outbound traffic of the mostly static content.