All new figures are meant to be OSGB which differs from OSGB:ST in obvious fashion.

Tynings Barrows Cave

Diff GPS: 

Centre of Cave Lid

E 347125.42   N 156414.00  H 266.24

Current:

E 47130 N 56380 H 256

Comment: Minor changes E & N I do not believe the new height

G.B.

Diff GPS

Top of Blockhouse Roof, immediately above NW corner of brickwork.

E 347585.51 N 156234.80 H 252.71

Current, as far as I can tell:

E 47590.70 N 56237.30 H 252.98

Comment: Minor tweak to Easting, I think is needed. Northing bloody close but do change, height depends where the datum really was don't change.

Charterhouse

Diff GPP:

Measurement taken 0.26 m above prime survey point in gate frame

E 347747.05 N 156201.99 H 254.00

Current:

E 47750 N 56200 H 255

Comment: Minor tweaks only but do them.

Also:

Gruffy Field Mineshaft. This is 4m deep shaft to 4m south trending passage.

Diff GPS:

Centre of Grill

E 347708.50 N 156213.36 H 255.48

Current (MCRA)

E 4769 N 5619 H 256

I do not doubt the new figures are better and have amended MCRA as below:

E 4770 N 5621 H 255

Rabbit Mine. 3m shaft with 5 m of passage at bottom

Centre of Grill

E 347685.28 N 156193.05 H 256.15

Current (MCRA)

E 4771 N 5622 H 256

maybe this explains why it always takes me so long to find this place; have amended MCRA to

E 4768 N 5619 H 256