A question for UK steam locomotives enthusiasts and keen geographers.

The GWR named a series of locomotives (68xx) after famous Granges
(i.e. a substantial farm complexes) in their region of operations.

One of these locomotives was called the ?Penrhos Grange? ? 6868.

The question is, where was Penrhos Grange the farm i.e. the building.
I can?t find it on a map or find a picture. Can I go and see it?
Penrhos is Wales but I can?t find a Grange on the map.

Obviously, Penrhos Grange was in medieval times property of Grace Dieu
Abbey in Monmouthshire:

"Supporting evidence for being former medieval monastic holdings in
?Atlas of Cistercian Lands in Wales?, David H. Williams; he identifies
Grace Dieu Abbey holdings as: water mill on Trothy at Hendre, Penrhos
Grange..."
http://www.monmouthshire.gov.uk/NR/rdonlyres/642F4FB5-FB98-4D79-B0D5-595810D70D87/0/LANDMAPVolume5CulturalAspectTA13MB.pdf

Furthermore, it seems that this very farm once known as Penrhos Grange
is now named Grange Farm:

"From Llantilio Crossenny the Offa?s Dyke Path goes south-east along a
side road to Penrhos Farm, along a track through the orchards and past
Grace Dieu?s Penrhos grange (now Grange Farm)  to Llanfihangel Ystum
Llywern. Then follow the track along the banks of the Trothy. The farm
across the river is Court Farm, whose name suggests it was the centre
of Grace Dieu?s Crug-yr-Onnen Grange. The track continues for about a
mile as a footpath across the fields then crosses the Trothy by a road
bridge and continues across the fields to Grace Dieu."
http://web.archive.org/web/20050213094505/http://cistercian-way.newport.ac.uk/cwmhir-gracedieu.html

Scriptor