The 1891 Census for Wales on Ancestry.co.uk shows us that the Cavanna family were living in Llanllechid at 14 Ciffodeu Street.
Head of the household was Lewis Cavanna born in Liverpool a Hawker by trade.
His wife Ann was 38 years of age, born in Saint Asaph and their children were Louis Francis age 9 and John Joseph age 1 both children were born in Saint Asaph.
The 1901 Census finds Louis Kavanagh residing at Plas Coch in Cefn (entire) which is shown as Part of St. Asaph in Denbighshire.
The Head of the household, Elizabeth Hughes a Widow, 62 years of age, is a Farmer Employer by trade. She has two children, John age 29 listed as Farmer’s Son by trade and Ann age 31.
Louis Kavanagh age 19 is shown to be a Cattleman on Farm by trade born in Llanefydd.
There is also another Servant at this address, Thomas Roberts age 19 who is a Carter on farm by trade.
Unfortunately I cannot find any of the family on the 1911 Census.
I found this article in the Denbighshire Free press dated 2nd January 1915.
I then found this medal card on Ancestry.co.uk
The following information is from The Long Long Trail website.
The officers and men of the ASC – sometimes referred to in a joking, disparaging way as Ally Sloper’s Cavalry – were the unsung heroes of the British Army in the Great War. Soldiers can not fight without food, equipment and ammunition. They can not move without horses or vehicles. It was the ASC’s job to provide them. In the Great War, the vast majority of the supply, maintaining a vast army on many fronts, was supplied from Britain. Using horsed and motor vehicles, railways and waterways, the ASC performed prodigious feats of logistics and were one of the great strengths of organisation by which the war was won.
At peak, the ASC numbered an incredible 10,547 officers and 315,334 men.
All Mechanical Transport Companies were part of the Lines of Communication and were not under orders of a Division, although some (unusually known as Divisional Supply Columns and Divisional Ammunition Parks) were in effect attached to a given Division and worked closely with it. Those in the Lines of Communication operated in wide variety of roles, such as being attached to the heavy artillery as Ammunition Columns or Parks, being Omnibus Companies, Motor Ambulance Convoys, or Bridging and Pontoon units.
Soldiers who served in the Mechanical Transport usually had the letter M as a prefix to their number.
Unfortunately I could not find a Service record to prove that this is the Louis Francis Cavanna/Kavanagh on St. Asaph Memorial.
The facts that we do have are that Louis appears on the St. Asaph WW1 Memorial.
This story is very much a work in process and I look forward to adding more information as it becomes available.