Dear Margp
if your man was in the artillery, either RFA or RGA then he wouldn't have been in any regiment; the artillery had their own structure which existed alongside the infantry regimental system. That's not to say that his Battery did not support the Worcesters, just that the two groups would have been quite separate. Artillery Batteries are notoriously difficult to track as they tended to be sent all over the place, wherever the need was greatest.
jds1949