This is guesswork but the Tour highlights are only made each evening, so it probably has to be transferred, transcoded and mirrored onto the network of download servers before it's available and that takes time. The DVB-S broadcast version is about 2Gb - the internet version will be smaller, but that still means processing 2Gb of show and I suspect the internet version will still be about 700Mb.
Library programmes like the Professionals are already encoded and probably even mirrored, so they'd only need to enable some links in the software to make it available, which is quite a quick task.