There are nuclear designs that follow load just fine. The UK just didn't build them. Also, the designs that load follow are usually liquid fueled reactors, not solid fueled ones which are normally built. PWRs generally have the lowest utility costs (the actual cost you pay, not the cost to build which is normally quoted) of any power source we have tried. Even the fast-sodium reactors the Soviets built can't match their price. That's part of why building stock nuclear designs works so well (eg the French) but trying to build experimental reactors doesn't. And when you try a new design, you have to build a pilot plant first to work out the kinks. The British always skip this step and this shows in the results.

Load following for nuclear is not a technical but an economic problem. For high capex generators you want to run them at a high load factor to be profitable.