Had a look on the 1901 census and there is only one TYAS couple living in Devon at the time:
John Abram TYAS b.1842 Canterbury, Kent Retired colonial newspaper proprietor Blanch Arabella TYAS b.1869 Southwark, Surrey (wife) Justine G. SLEEMAN b.1845 Islington, London (mother-in-law) Topsham, Devon RG13/2032/28/3
Their marriage is on FreeBMD - Mar 1900 quarter.
This couple also appear on a Rootsweb tree, which follows the SLEEMAN family amongst others (according to this tree the SLEEMANs appear in Burke's Peerage).
Yet again, another link to my family (I also had a John Abram TYAS - perhaps this one was the son of mine?).One of my female TYAS relatives married into the HARDEN family, and one of the HARDENs was a newspaper proprietor too, as was a possible member of my family, one Richard TYAS (I'm looking for a London-based Richard Henry TYAS, cannot yet link him to Richard TYAS, attorney and newspaper propr. of London, roughly the same age).
It seems highly possible that we share a TYAS link.I'm happy to share what I have and would love to hear if you have worked any further back since your post.