"a lot of the old numbers were re-used for new records - thus there are actually two different YB-1017s, one on Young Blood from 1970, and this one on Young Blood International from 1973".
Gosh, that's not a very nice thing to do, is it? How dare they confuse people like that? TWO DIFFERENT RECORDS WITH THE SAME NUMBER???? It's unthinkable, it's sacrilegious, it simply shouldn't be allowed!!!! There ought to be a law against such things!
Young Blood catalogue numbers are a bit of a mess. When Young Blood became Young Blood International, in 1972, a lot of the old numbers were re-used for new records - thus there are actually two different YB-1017s, one on Young Blood from 1970, and this one on Young Blood International from 1973. To add to the confusion, some Young Blood singles were reissued on Young Blood International with their old catalogue numbers. The different listings can be compared on my Seventies Sevens site, on the Young Blood and Young Blood International pages.
I know this single charted in 1973, as a result of a TV commercial, but wasn't it released in 1970? Check out YB 1018 and you'll see that was indeed 1970, so surely YB 1017 was 1970 as well. For some unknown reason, there is no date on the label of this one.
Nice One Cyril was originally written as a football song, and there were other football-themed songs in the charts in 1970 (Back Home, Belfast Boy, etc.), so I would say this was released in 1970 (probably with the older white label with red print), missed the charts, and was re-issued in 1973 with the label design shown here.
Another Young Blood single which charted much later than its first release was Python Lee Jackson's In A Broken Dream (YB 1002). That kept its original number when it charted in 1972, so I guess the same is true of Nice One Cyril.