Revert "catch service worker error?"
Revert "catch service worker error?"

This reverts commit c14cfe8917c1f1c23ccd4bbd25a7b40d6c5d6b2b.

jclgoodwin/bustimes.org.uk,jclgoodwin/bustimes.org.uk,jclgoodwin/bustimes.org.uk,jclgoodwin/bustimes.org.uk