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... Holcus lanatus is Holcus mollis (wood soft grass).
The habitat is right for Holcus lanatus - Holcus mollis is a plant of woodlands and hedgerow bases.
Whilst Holcus mollis has white inflorescences, Holcus lanatus varies from white to quite red or purple, so we can't say definitely which it is from the colour.
In that absence of that distinction, the next thing to look at is the habit (tufted in H. lanatus and rhizomatous in H. mollis) and the hairiness of the plants, neither of which is clear enough in these photgraphs for me to be sure.
Bottom line - I think that this is Holcus lanatus, but I'm not sure enough for recording purposes. Someone more familiar with Holcus mollis than I am may be able to identify this one.
Much appreciated. We're heading back there now for a couple of days, we'll take a closer look as you suggest and hopefully post a new obs with relevant detail next week.
Many thanks, Paul
Lat/Lng: 50.9171, -0.1498
OS grid ref: TQ301147