For those interested with Vimeo note that they, until very recently, would upgrade SD videos uploaded to HD!
Effectively this has ceased. Basically, Uploads must meet their newly set up "transcoding" in this respect as follows:-
We recently introduced a new transcoding profile at 540p. Prior to this profile, we treated all videos around this size as 720p, even though they were not technically 720p; we did this to avoid reducing the quality all the way down to 360p, the next lowest profile. With the new 540p profile, these videos can be handled more appropriately given their dimensions.
In order to be considered “720p” on Vimeo, your source file’s larger dimension must be at least 1216px, OR the smaller dimension must be at least 684px. = Vimeo Support.
Keep plodding on!