Hi
There's an online tree which includes John Edward Roberts, son of Elias and Winifred and born 25 Nov 1879, Trevor, Llangollen.
He is recorded as a Railway worker, dying in Chirk (at 5 Charles Street, which is the Rhosywaun part of Chirk) on 25 April 1946. He married a Beatrice Murrow on 15 Oct 1907 in Penzance, and they had 6 children. The tree contains a photo of him.
This tree can be viewed via Mundia -
http://www.mundia.com/gb/He is also recorded here:
https://familysearch.org/pal:/MM9.1.1/X726-6N5 There are a number of John Edward Roberts, born circa 1880, included in online trees. It might be worth rechecking the information that you have.
What is his occupation on Elizabeth's birth certificate and/or the marriage cert of 1911?
The GRO Marriage index records him as just John:
Sept q, 1911, St Asaph, 11b 538 (a civil marriage so no online records)
Gadget
PS - the marriage certificate should give the name and occupation of his father as a further check