Looking like something out of 'Alien'.
No identification made yet.
No interactions present.
This is a spider moulting. Described as trying to remove a glove with the other hand behind your back!
LH picture is too dark to go further, but perhaps knowing where "Two Tree Island" is could limit the search. Freshly moulted spiders, like dragonflies, are much paler immediately afterwards, so go back to the island and take another shot!
Lat/Lng: 51.528930974706, 0.52451133728027
OS grid ref: TQ752841
Not far from Leigh-on-Sea, Essex