Firstly, thankyou chwiliwr and Trish, for your help - also Jon, your kind offer is greatly appreciated.
In 1939 Edward Wallwork Horrocks along with his wife Mary nee Ancell were the Inn Keepers of the Cambrian Inn in Llanfyllin. Mary's mother, Mary Ann Ancell was also staying with them.
My mother in law now remembers that her uncle, who was the proprietor of the other hotel was Uncle Harry. Edward Wallwork Horrocks had a younger brother, Henry (Harry) Wallwork born 10 Apr 1903 Pendleton, Salford, Lancashire who married in 1931 in Salford Lancs - Hilda Brierley born 5 Jan 1906.
In 1939 Henry (Harry) Wallwork and wife Hilda were living at 24 Osborne Street Salford Lancs. His occupation was Master Painter. If this were indeed he (who was the hotel owner in 1948), then he would have purchased the hotel in Llanfyllin from whoever owned it in 1939 possibly to live closer to his brother, Edward and family.
Unfortunately Trish, I can't link Thomas Williams to our Williams family, try as I may. To complicate things M.I.L also has another Uncle - Harry Williams born abt. 1895 Ramsbottom Lancashire who married Edith Rostron born 1899 Charlestown, St George, Lancashire. They married in 1920 but I can't find them in 1939 census. I've put this one on the back burner however, as he is a step uncle - but anything is possible!
Thanks for the suggestion chwiliwr, I've searched the 1939 census for all of those family members who were living at that time and I couldn't any, except Edward Wallwork Horrocks and family, living in Llanfyllin.
I thought that if I could find where records were kept of Landlords/Owners of Hotels/Inns in the mid to late 1940's Llanfyllin that I could hopefully find them.
Margaret