Paddy,
There is a QSA to Pte H Clydesdale 2419 2nd Bn Royal Irish Rifles, entitled to clasps Cape Colony, Transvaal & Orange Free State. I can also see a KSA with Clasps 1901 & 1902 to Pte H Clydesdale 2492 5th Bn Royal Irish Rifles (highly likely these are both to the same man) as the numbers don't appear against another H Clydesdale.

There is a Militia attestation for this soldier as 2492 first name Hugh, states he was mobilised 15Jan1900. This would correlate with your man, possible when transferring from the militia to the reserve to the 2nd Bn, his number did change. Worth a deeper dive into. Regards Mark