I found some reports in the newspapers which appear to refer to your Theodore Wendt.
From Cheshire Observer 12 Oct 1895 :
Cardiff Bankruptcy Court
Thomas New, late of Ellesmere Port , came up for public examination. The debtor , a clothier , was formerly in business at Cadoxton when he went by the name of Theodore Wendt. He admitted owing £150 , since repaid, and moved to Ellesmere Port where he went by the name Thomas New. He was in partnership with his father and came to Barry in April 1894 where the business failed.
(I noticed that Robert Wendt was born 1894 in Barry Dock which seems to fit with the above.)
A further notice confirming the Receiving Order states :
Theodore Wendt , lately trading as New & Co, Holton Road , Barry Dock , lately trading at Dockland Street , Ellesmere Port, Cheshire , clothier and outfitter.
I've found 2 baptisms for siblings of Reginald James :
Wilhelm Henry Wendt 8 May 1895 son of Theodore Wendt , clothier , and Elizabeth of 126 Holton Road at Cadoxton Juxta Barry
also Theodore Ferdinand Wendt junior baptised at the same time.
This hasn't led to my finding Reginald James unfortunately !