Ive been told the first object is a crab but the other appears to wrap around the pebble so any ideas on what it is are welcomed.
Both items found on the Isle of Sheppey at the minster cliffs.
1&2. The flint contains a layer of something that has an organic (ie. fossil) look to it, but I can't see enough detail to hazard much of a guess; all I can say is that the internal structure is not right for a bivalve.
3&4. Intriguing! From photo 4, I see three 'cells' each with some darker structure towards the centre. Although there is a lot of apparent randomness, there is also consistency in the way the dark structures are clearly separated from the edges by the pale matrix. When I saw the first photo (3), I thought we might be looking at the aristotle's lantern inside an echinoid (sea urchin), but seeing three squashed together (photo 4) ruled that out. With a low degree of confidence, I suggest it might be remnants of one or more crabs.
Interesting fossils have been recorded from Sheppey, eg. as documented by Edward Jacob in 1777 (http://www.sheppeyfossils.com/pages/g_b3.htm). That description includes crabs and nuts, but also from the area are Dasornis (a large Eocene flying bird), a skull, lobsters, and snakes.
You might have to send/bring it in to the Angela Marmont Centre to get a palaeontologist to take a close look.
Looks like a crab in image 3&4, in image 3 you can see the cross sections of worn out legs but on the fourth image it looks to be heavly pyratised making it hard to prep, although the matrix looks to be softer.