I have been asking around friends and family as to what this insect is. One of them recommended I try here.
The body was approximately 4cms in length.
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The Speckled Bush-cricket has a dumpy body, compared with the longer and thinner body of both cone-head species. Male Speckled BC also has very tiny round wings, whereas even the SW cone-head has wings about half the length of its body. I presume your 4cm included the legs. For a Speckled BC the length of the body only is a bit less than 2cm.
More information here -
Lat/Lng: 52.2, -1.6
OS grid ref: SP3163