No. They did try a web cache system (to help solve with other spead issues) but it caused too many issues and it was withdrawn. It may be introduced again at some future date but I have no idea if or when this will be.
Web caches can improve web page downloading but not file downloading as files tend not to be cached, only things like HTML pages and images. They can also cause problems due to not supplying the correct pages that reside on the actual websites when they have been updated and the cached copy has not. This was the main issue with the plusnet web cache.