Hi Keiron,
I enjoy ca 13k VQ-Tower Bridge (TB) and back. Start at Budgeons - through Boardwalk Place, cut through CW by Lehman Brs, pass Limehouse via Narrow Street, continue via Riverbank pass King Edward park, cross the Glamis Rd and then around the dock (northside) continue trough the park to Discovery way to Spirit Quay along the canal, at the end (up the stairs) under the bridge along the dock onto St Katharine's way and contonue to the Hotel (riverside). I love the sight of Tower Bridge and changin surface of the route.
A shorter route is ca 8k if you turn back at King Edward Park, but the last bit (From King Edward to TB) is more enjoyable.