1. The assumption of an ice-free enclave or corridor comes initially from an assertion by Charlesworth that South Pembrokeshire, south of his imagined "South Wales End Moraine", was an area of "Older Drift". This was carried through by DQ Bowen and others who thought that there was a pre-Devensian "Penfro Till Formation" across the landscape to the south of Mynydd Preseli. However, the type localities (West Angle and Llandre) are worthless and have never been adequately described. At one of them, there is no till, and at the other the stratigraphy has been misinterpreted. There are ancient till deposits in Pembrokeshire, but not at those two named sites.
2. There are many more extensive spreads of glacial and fluvio-glacial deposits than those shown on the map above, in the areas deemed to be outside the LGM limit. Some of them, at least, appear quite fresh, and some even have surface expression. They are by no means all "degraded or denuded" and they are not restricted to hilltops or interfluves, as claimed by some. The evidence of these extensive deposits is portrayed on the BGS map viewer.
4. The glacial and fluvioglacial deposits in the valleys and on the clifftops of South Pembrokeshire are so abundant and so fresh that they have to be Devensian. The exposures occur at multiple locations including St Bride's Haven, Westdale, Dale, West Angle, Freshwater West, Swanlake, Flimston, Stackpole Head, Lydstep, St Florence and Ragwen Point near Pendine.
6. The glacial and fluvioglacial deposits around Picton Point and Landshipping, right in the centre of the county at the confluence of the two Cleddau rivers, cannot adequately be explained without invoking a complete ice cover across Pembrokeshire. I have another report of fresh till near Haverfordwest. The sheets of fluvioglacial gravels that partly fill the Western Cleddau valley both to north and south of the Trefgarn Gorge are interpreted as deposits linked to catastrophic Late Devensian ice wastage.
7. There are apparent trimlines and glacial deposits at a variety of altitudes on the northern side of Preseli, up to an altitude of at least 340m, and possibly as high as 420m. That was probably the altitude of the highest Devensian ice surface associated with Irish Sea ice. Ice must have filled the Cwm Gwaun depression, and there are apparent morainic features above and on the south side of the meltwater channel, and at Cilgwyn and Tafarn y Bwlch. I now think that the assorted morainic ridges and glaciofluvial mounds in and around the Preseli uplands may be associated with retreat stages or short-lived readvances -- still to be defined.