The cache is not at the published coords. In order to work out the location of the cache, simply work out what to do with these...
A1, B1, C1, D1, E1, F1, G1, K1, M1, O1, P1, Q1, R1, S1, T1, U1, A2, G2, J2, 02, U2, A3, C3, D3, E3, G3, I3, K3, 03, Q3, R3, S3, U3, A4, C4, D4, E4, G4, J4, L4, 04, Q4, R4, S4, U4, A5, C5, D5, E5, G5, J5, 05, Q5, R5, S5, U5, A6, G6, J6, K6, L6, 06, U6, A7, B7, C7, D7, E7, F7, G7, I7, K7, M7, O7, P7, Q7, R7, S7, T7, U7, I8, K8, L8, A9, B9, C9, E9, F9, G9, H9, I9, K9, L9, N9, O9, S9, A10, B10, C10, D10, F10, H10, L10, O10, P10, R10, T10, A11, B11, D11, G11, K11, L11, P11, S11, U11, A12, B12, C12, D12, E12, I12, J12, K12, L12, M12, N12, O12, P12, Q12, R12, S12, A13, D13, G13, I13, K13, L13, O13, P13, U13, I14, L14, N14, P14, R14, T14, A15, B15, C15, D15, E15, F15, G15, I15, J15, L15, O15, T15, U15, A16, G16, I16, L16, N16, P16, R16, U16, A17, C17, D17, E17, G17, I17, J17, K17, O17, Q17, A18, C18, D18, E18, G18, J18, L18, N18, S18, T18, A19, C19, D19, E19, G19, I19, K19, M19, O19, P19, Q19, R19, U19, A20, G20, I20, K20, L20, M20, N20, Q20, R20, T20, U20, A21, B21, C21, D21, E21, F21, G21, I21, K21, M21, N21, O21, R21, U21
...and this!
No geocheck required, once you've solved the puzzle you'll know the coords are spot on!
Please note there is no need to bushwhack to get to the cache. If you find your way blocked by undergrowth, please find a way round rather than going through. This cache has been placed with full permission of the National Trust.