Quoted from Tophervette:Welcome to the club of Doctor Who pinball. The plastics are most all listed on Ebay. One guy in the Russian Federation sells the whole set. Another guy sells them separately. There is pinball website in the UK that I have gotten some parts from that are not stocked at my favorite Marcos site. https://www.pinball.center/en/shop/pinball-parts-by-game/doctor-who/?p=1 They have all the plastics too. Share a picture of your game when you get a chance.
I have an extra set of Dalek Sling shot plastics if you happen to break one. During my restoration, I chose to replace the screws and nuts with shiny new ones and added washers to the top of my plastics.
watch out on plastics from pinballcenter (besides other items including artwork)-they are known for their inferior artwork quality
Better than missing plastics but far away from the originals or good repros