Service from Boer War to WW1

I'm struggling to confirm my Grandfathers service history in the Worcester's from when he served in South Africa 1901, 1902, to when he came out in the early 1920's. I believed he served straight through from the Boer War to the early 1920's but is it possible that he could have come out for a time then returned to the Worcester's still with his original service number? I have copies of his WW1 medal card and his Boer War medal entitlement, I'm also in possession of his medals so I know his service number is the same for both periods, I believe his service records were lost with many others during WW2.
I ask this as looking at my family history he seems to pop up with his wife and children on the 1911 census working in a factory, could he have been retained as a territorial or reserve in this time and kept his service number? or am I barking up the wrong tree?
He was Sergeant Harry Allen 5958 and finished his time in the regiment living and working at The Shrubbery, Kidderminster.
I would be grateful for any thoughts on this,
Regards,
Martin.
I ask this as looking at my family history he seems to pop up with his wife and children on the 1911 census working in a factory, could he have been retained as a territorial or reserve in this time and kept his service number? or am I barking up the wrong tree?
He was Sergeant Harry Allen 5958 and finished his time in the regiment living and working at The Shrubbery, Kidderminster.
I would be grateful for any thoughts on this,
Regards,
Martin.