Here are the soundings for what I think was the day you mean. Camborne is in deepest Cornwall.
Code:
03808 Camborne Observations at 00Z 02 Feb 2005
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PRES HGHT TEMP DWPT RELH MIXR DRCT SKNT THTA THTE THTV
hPa m C C % g/kg deg knot K K K
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1030.0 88 7.8 4.5 80 5.15 10 12 278.6 292.9 279.4
1029.0 96 7.8 4.2 78 5.05 9 12 278.7 292.7 279.5
1020.0 167 7.4 3.7 77 4.92 5 13 279.0 292.6 279.8
1000.0 327 5.8 3.3 84 4.87 354 14 278.9 292.5 279.8
993.0 384 5.3 3.2 86 4.87 350 15 279.0 292.5 279.8
963.0 634 3.0 2.7 98 4.85 11 15 279.1 292.6 280.0
950.0 744 2.3 2.0 98 4.69 20 15 279.6 292.6 280.3
936.0 864 1.6 1.3 98 4.51 34 16 280.0 292.6 280.8
925.0 959 2.8 -6.2 52 2.61 45 17 282.2 289.8 282.6
917.0 1030 7.6 -12.4 23 1.62 49 19 287.8 292.8 288.1
914.0 1057 8.2 -18.0 14 1.02 50 20 288.7 291.9 288.9
905.0 1139 10.0 -35.0 3 0.22 48 21 291.3 292.1 291.4
887.0 1305 9.0 -36.7 2 0.19 45 24 292.0 292.6 292.0
853.0 1628 7.0 -40.0 2 0.14 31 22 293.2 293.7 293.2
850.0 1657 6.8 -39.2 2 0.15 30 22 293.3 293.8 293.3
820.0 1948 4.4 -38.8 3 0.16 20 20 293.7 294.3 293.8
777.0 2385 0.8 -38.2 4 0.18 16 23 294.4 295.1 294.5
772.0 2436 0.4 -38.3 4 0.18 15 23 294.6 295.2 294.6
739.0 2784 -2.0 -38.7 4 0.18 0 25 295.6 296.3 295.6
712.0 3079 -4.1 -39.1 5 0.18 3 24 296.5 297.1 296.5
700.0 3213 -5.3 -29.3 13 0.49 5 23 296.6 298.2 296.7
Sure enough, 1.6 degC at 864m, 10.0 at 1139m.
Code:
03808 Camborne Observations at 12Z 02 Feb 2005
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PRES HGHT TEMP DWPT RELH MIXR DRCT SKNT THTA THTE THTV
hPa m C C % g/kg deg knot K K K
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1029.0 88 6.8 2.6 75 4.51 350 11 277.7 290.2 278.4
1028.0 96 6.8 2.2 72 4.38 350 11 277.8 289.9 278.5
1026.0 112 6.8 2.2 72 4.39 349 12 277.9 290.1 278.6
1005.0 279 5.2 1.7 78 4.32 342 15 277.9 290.0 278.7
1000.0 319 4.8 1.6 80 4.31 340 16 277.9 290.0 278.7
984.0 449 3.5 1.2 85 4.25 335 19 277.9 289.8 278.6
955.0 691 1.0 0.4 96 4.14 339 21 277.8 289.3 278.5
944.0 784 0.4 -0.1 96 4.03 340 22 278.1 289.3 278.8
925.0 947 -0.7 -1.1 97 3.83 340 23 278.6 289.4 279.2
895.0 1210 -2.3 -2.8 96 3.49 331 26 279.6 289.5 280.2
891.0 1247 -1.4 -4.2 81 3.16 330 26 280.9 289.9 281.4
867.0 1467 4.2 -12.8 28 1.66 320 26 288.9 294.0 289.2
854.0 1590 4.5 -14.0 25 1.52 315 26 290.5 295.2 290.7
850.0 1628 4.6 -14.4 24 1.48 315 26 290.9 295.6 291.2
836.0 1763 4.4 -18.6 17 1.06 318 28 292.1 295.5 292.3
833.0 1792 5.4 -23.6 10 0.69 319 29 293.5 295.8 293.6
824.0 1881 5.8 -23.2 10 0.72 321 30 294.8 297.2 294.9
819.0 1931 5.4 -23.6 10 0.70 322 31 294.9 297.2 295.0
786.0 2261 2.9 -24.8 11 0.65 330 36 295.7 297.9 295.8
745.0 2690 -0.5 -26.4 12 0.60 335 34 296.6 298.6 296.7
716.0 3009 -2.9 -27.6 13 0.56 335 38 297.3 299.2 297.4
700.0 3190 -4.3 -28.3 13 0.53 335 40 297.7 299.5 297.8
685.0 3360 -5.7 -29.7 13 0.48 339 41 298.0 299.6 298.1
682.0 3394 -6.0 -29.9 13 0.47 340 41 298.0 299.7 298.1
and 12 hours later a similar inversion but at the sort of level you describe.