Service from Boer War to WW1

[Martin]

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.