Western Wander v3

Revised version of my Thornton Heath to West London route, now that Hammersmith Bridge has reopened and CS9 is (nearly) finished.

Changes:

- Avoid Streatham Common rookery hilltop.

- Use path to go alongside A23 to Streatham Common (Northside) crossing.

- Tooting Common uses the designated route. Unpaved surfaces in places.

- Wandsworth Common, stay west of the tracks but avoid the narrow "ponds" path - diagonally across to Q4 path near Lyford Road.

- Use Hammersmith Bridge instead of Wandsworth (note - there's a nasty gap in the riverside path Putney Bridge south side, be careful here; surfaces past Barn Elms are unpaved and can be muddy at times).

- Use CS9 instead of Hammersmith riverside. Still under construction at time of writing but should be a few weeks from completion.