The Lost land of Lyonesse revisited

In a previous post, I mentioned the work of Shennan and Horton (2002) about sea level change around Britain through the Holocene.

I showed a visualisation of the West Cornwall coastline as it may have been around 12,000 years before present.

After downloading further bathymetry via the UKHO INSPIRE portal, I present an updated version covering the whole area around Cornwall.

Much of this came as .csv point data, which I had to grid, and use the QGIS Concave Hull plugin from the Processing toolbox to restrict the interpolated grid to where there was data.

In some areas, there are gaps in what is currently available at high resolution so it falls back to low-resolution data.

Based on my reading off the graphs in Shennan and Horton, the sea level rise at this time should be similar across the area covered here:
 

Site Number

Site Name

Lat

Long

RSL 1kyr

RSL 2kyr

RSL 3kyr

RSL 4kyr

RSL 5kyr

RSL 6kyr

RSL 7kyr

RSL 8kyr

RSL 9kyr

RSL 10kyr

RSL 11 kyr

RSL 12 kyr

42	Pembroke	51.8	-5.1	-0.8	-1.6	-2.4	-3.2	-4	-9.2	-14.4	-19.6	-24.8	-30	-35.2	-40.4
43	Glamorgan	51.5	-3.7	-2	-4	-6	-8	-10	-13.6	-17.2	-20.8	-24.4	-28	-31.6	-35.2
51	Devon	50.4	-3.5	-1	-2	-3	-4	-5	-10	-15	-20	-25	-30	-35	-40
52	Cornwall	50.2	-5.5	-1.4	-2.8	-4.2	-5.6	-7	-11.6	-16.2	-20.8	-25.4	-30	-34.6	-39.2

It is clear there were substantial areas of land that were disappearing in the millenia after the reoccupation of Britain after the last glacial maximum (with this map corresponding to the cold spell of the Younger Dryas).
In the period of time, between 12kyr BP and 8kyr BP sea level rose by 20m, which corresponds to half a metre every century.
Especially in the large expanses of gently sloping terrain off the north coast, it would be likely that coastal retreat would have been noticeable by people within a single lifetime.

A version speculating about woodland colonising the lowlands: