I have a route that can pack more climbing in 60k just within the hills of north London, Essex is as flat as it gets. For flatter orography see Belgium or Nederland.
Sorry mate, didn't realise we were in a 'how many hills can I climb' competition. The Shark seems to have that particular itch scratched, for me at least. Just found it a bit harder than I expected! Although the chronic hay fever didn't help - maybe it was as much that as anything.
Oh, it was a great ride, just not as flat as I'd expect in Essex...