R Shipman

Hi, I need to replace some of the runners on my parents' kitchen drawers. The kitchen was fitted probably in the late 1980s and is in very good condition otherwise. Does anyone know where I can get a direct replacement for the runners (or boxes) please? Failing that, what would be the best alternative? Many thanks, Ronnie Here are the details: On the runner is written: SHEERGLIDE R A 500 Use BS 570 runner. On the box is written: RA CONTOUR 80 SOLE MANF LB Plastics Limited. Approx dimensions mm: Runner: 411 x 23 x 10 mm (L x H x D) Box: 460 x 445 x 80 mm (W x D x H) Photo: https://photos.google.com/photo/AF1QipMTzEDKoztNNKom4XosGHNFcyZ5x3m-d8hlGk5B