The UV inside the ride is an interestingly one really. Currently, it doesnt look how it was intended but there's an interesting story to it! When the ride was created, it had a pretty bespoke UV technique, by high quality scenic artists (some of the best for UV in Europe!). It wasn't the 'glow in the dark' effect people think of as UV now, it was very subtle, not your standard blue, pink, yellow. It allowed scenery to be really detailed, without shining visible light everywhere, still in surrounding darkness. Flat shapes could look like real stonework, or all sorts of scenic details like overhanging branches and foliage could be seen without spilling light everywhere. It all relied on the blacklight effect. However the UV lighting was mostly all removed by 1993. Alton Towers's marketing department wanted to change the ride to be 'darker and scarier' because (despite pressing for a family attraction throughout its design) they launched the Haunted House as being incredibly scary. The original ride was intended to be more surreal and surprising than pure horror, personally I think it works best this way. You could call it 'Tim Burton-esque' I guess. So the ride was mostly dropped into darkness, meaning loads of incredible scenery that had previously relied on blacklight no longer got seen. A lot was also painted over. In recent years there had been some at Alton Towers who noticed how much of the original scenery had UV treatment, so wanted to bring it back. In 2016/7, the first wave of UV didn't look too bad, but the tubes were visible and distracting (and the rest the new lighting was very poor that year). The surviving UV paintwork had also faded much after so many years, and the original studio that innovated this style of UV artwork had since closed. Unfortunately the latest wave of UV lighting this year was LED and totally the wrong method, despite good intentions. With the current state of LED UV, I don't think it should even be called "UV" (nor do many in the lighting industry, which I am not). It produces visible light, showing mechanisms or revealing scenery as actually being flat shapes. Its brightness looks much cheaper and more 'glow in the dark' than the effect was ever intended to be. Interestingly there are LED lights currently being made by some brands that claim will produce true blacklight, but I dont think theyre available just yet. Of course, the old flourescent lamps and tubes are still available. However the UV strobes for flying heads need a special filter that is no longer manufactured, so would need to be especially sourced, until LED technology catches up.