William ap Gruffydd, of Cochwillan - "The house in Cochwillan is considered one of the best examples of a late medieval, non-defensive residence in Wales. To date, it has maintained an almost unchanged appearance"

Built by William in 1465, and essentially unchanged over time, having been unused, then converted to a barn and warehouse. Considered by several poets to be a place at the time of fine hospitality there, one vowing to stay there for the rest of his life. Poems are written about this manor.

A few of the links:
https://coflein.gov.uk/en/site/26298/
https://medievalheritage.eu/en/main-page/heritage/wales/cochwillan-...
https://en.wikipedia.org/wiki/Cochwillan

Intel from link #1 above, which has some fantastic photography of the home:

"See the Centre for Advanced Welsh and Celtic Studies' on-line resource Guto'r Glyn.net poem 55 for Guto'r Glyn's poem in praise of Wiliam ap Gruffudd of Cochwillan. From the notes to Poem 55:

This is a poem of praise to Wiliam ap Gruffudd of Cochwillan in the parish of Llanllechid in Gwynedd which Guto composed when he was an old man. Wiliam's hospitality is thoroughly praised in the first 34 lines and Guto states his intention to stay in Wiliam's court for the rest of his life. It seems that the existing house at Cochwillan was built during the second half of the fifteenth century by Wiliam himself, although the poet Gwilym ap Sefnyn clearly states in a poem to Wiliam's grandfather, Rhobin ap Gruffudd, that there was a house at Cochwillan at the beginning of the century (see Williams 1997: 91). Smith (1975: 102) argues that Wiliam renovated or rebuilt the house sometime after 1485 when he was appointed sheriff of Caernarfonshire following the support he gave to Henry Tudor at Bosworth: `It is fair to surmise that Gruffydd [that is to say, Wiliam] built his great hall to support his newly exalted position in society, and he built it in the latest fashion for a great gentleman, with an outstanding hammer-beam roof, glazed windows and a side-chimney?".

Thought I would share, having researched the issue a bit.
Cheers!
Braxton