Thanks chaps,
As you've probably guessed I am looking at Ernest Long, KIA 9/8/1915 at Gallipoli with the NZEF. I'd go with your discovery that Ernest Long served with the 57th Coy, 15th Batt. IY. As you (David) suggest, the Wharfdale title seems to be more 'coloquoial' rather than a specific Imperial Yeomanry company designation, hinting at the location of many of the recruits for this company.
Thanks very much for all your digging.
Cheers
Phil