DoS attacks usually come from many IP addresses, so I would not worry about a
49 MB download from one IP address - that probably would not be considered a
DoS attack by any knowledgeable person, even though you might have seen some
similar, unwarranted assertions in this forum to the contrary.

I run a larger mirror weekly from one site (some of their pages change often)
openly and without any complaints.  I have even emailed them a few times to
point out that my mirror failed due to some error in their site -
occasionally, they forget a file, for example....

Cheers.