Few comments:

1) The images you've shared clearly show signs following the designated cycle route / way from East India Dock Road to Leamouth Road, across Lower Lea Crossing and towards Aspen Way.

2) The signs along Lea Valley Walk clearly show a pedestrian sign, which by default means no cycling based on the highway code. You don't need a dismount sign, that's the law.

3) You appear to be mixing up Silvocea Way with Lea Valley Walk, these aren't the same. 

4) Lea Valley Walk is not a share cycle path, nor are there any signs, maps or markings to suggest it is. This is a misinterpretation. 