Numbering gap between 8.3.3.1 and 8.3.3.3

Currently

In v19 the clause numbers jump from 8.3.3.1 to 8.3.3.3.

Proposed

Change 8.3.3.3 back to 8.3.3.2, as it was in v17.

8.3.3.1 Unobstructed forward reach

...

8.3.3.3 8.3.3.2 Obstructed forward reach

...

8.3.3.3.1 8.3.3.2.1 Clear space underneath an obstruction

...

8.3.3.3.2 8.3.3.2.2 Recommendations for toe and knee clearance

..

etc.