Paul,
As you say, he was certainly serving within the entitlement window for the RoM clasp and this is clearly indicated on the KLH roll. The interpretation of the rolls could be that he earned DoK from the KVR and then went on to earn RoM and OFS with the KLH. If that was the case, it could be expected that the RoM clasp would have been added at the same time as the OFS and be on the medal so its omission is unexpected. There would be no reason to remove it and, if there are no signs of removal, it would suggest it was never added to the medal. In cases like these, I do not know if the authorities would have sent him the RoM and OFS clasp joined together as a block as they did with other units. The problem would be that the DoK would need to be fitted between RoM and OFS to be in the correct order so perhaps the clasps were sent separately? Do the rivet between DoK and OFS look to be original?
I think I am changing my view and hedging more to a 60/40 belief that he should have QSA (3) RoM DoK OFS and that the RoM is missing for some reason. If the QSA had presented with 3 clasps I am sure we would not have questioned it.
With kind regards
David