I've never ever seen anything like this. It would appear that this functionality has been there for a while and was also triggered on the Queen's birthday[0]
Yeah, but, this displayed the article that I wanted to read, then redirected me to a queue system, now i'll eventually go back to the actual page. Its causing more work for the system. The ticketmaster queues block a heavyweight process (ticket search), not simple page displays.
This is the equivalent of ticketmaster not letting you see pages with lists of upcoming performances without waiting in a queue.
I can't say for certain about the Royal Mint, but the US mint certainly does experience such a load pattern. It responds by either crashing or failing to load, unfortunately. A lightweight order-taking site that pushes orders to a queue for fulfillment would be a massive improvement over the strategy they actually choose (per-household quantity limits).
Presumably the Royal Mint experience similar demand peaks occasionally when limited-release collectable coins go on sale?