Overhauling ATE calliper with new seals etc.The slider pins fit inside a rubber tube fitted to the calliper.Question is the original tube has a plastic sleeve inside it,the new one doesn’t.Slider pin is a tight fit but just concerned whether I have the right tubes,visually they look identical .Any ideas.

Found the answer from the supplier (fall over backwards).
The new slider pin bushes have been designed around not using a nylon insert which is no longer available anyway.