We just got this march in our folders. It's not very difficult - maybe a grade 3. Tempo is 112 and has a pretty nice euphonium part. Usually the counter melody is in the trio, but in this march by Mr. Takahashi it's in the first strain.
Below is a link to listen to an 'un-authorized' recording on YouTube. The recording is actually from "Japan's Best for 2003 High Schools". Our MD posted about it in the comments.
British Folk Song March - Hiroki Takahashi
Note: The link has more than one march. "British Folk Song March" is the first one and a bit less than 4 mins long.