Yes, welcome - hope the fog has cleared!
Canvey is a great example of a bvrownfield (ex-industrial) site that supports much more wildlife than the average bit of British countryside! The habitat is very distinctive, supporting short grasses, ruderal flowers and therefore is attractive to many insects. It also holds heat from the sun, attracting thermophilic organisms.
It's not unique, there are plenty of similar habitats in SE England (and elsewhere in the world) but these, unfortunately, tend to be regarded as wasteland by developers and planners. It was a severe struggle to save Canvey Wick but hundreds of other sites (especially along the Thames Corridor) will be built upon - housing, roads and supermarkets
. Some very good ones in the lower Lea Valley will be destroyed for the Olympics ...