Hello Jom and Hugo,
I hope you don't mind me contributing to this thread.
There is no trace of Llwyn Helig in the 1841 census for Llandudno either. The Gogarth farms can be found on the last 4 pages of the 1841 census, reference HO107/1389 Book 3, Llandudno enumeration district 3, folio 20, pages 29-35 or so.
On page 33 there is a Mary Owen, Farmer, aged 70, at Gogarth Farm. Further down the page can be found an Evans family, head of the household, Griffith Evans, aged 40, Farmer.
I noticed a number of families by the name of Evans in the town in 1841.
As regards Llwyn Helig, I wonder if this was near to the Gogarth farms in view of the association between Helig and that area of Llandudno. There is Llys Helig Drive there today.
Helig