If that one's the same as the one I bought (from a different ebay shop - looks the same to me), it isn't long enough to get a tommy bar through - the mainshaft is in the way! I found an old socket that just fitted into the end (think it was a 5/8" Whitworth) and had it welded into the box spanner. Works a treat now. But before doing this, the box spanner wasn't up to the job.
The socket sizes given above, plus the smalller sizes you've already got, should be useful for just about everything on a T140. Only things they won;t fit are steering head adjuster, fork top nouts & front wheel spindle bearing large nut, and I think that's about it. Thses are easy enough to turn using a large adjustable spanner anyway.