Google does not like the starting address you entered.
When I search your starting address:
92 Higher Drive, Purley, Surrey, CR8 2HJ, United Kingdom
through maps.google.com, it comes back as:
92 Higher Dr, Croydon, Greater London CR8 2, UK
If i replace your address in the map js file:
full: '92 Higher Drive, Purley, Surrey, CR8 2HJ, United Kingdom',
with the one from google:
full: '92 Higher Dr, Croydon, Greater London CR8 2, UK',
the directions work.