JP i found the problem!
You put the end date BEFORE the start date, so it doesn't appear on the calendar...
Start: 2017-07-07 12:00:00.000
End: 2017-06-09 00:00:00.000
I'll find it online and fix it, no worries.
There's 4 in total like this...
Boxing Day Meets,Gloucestershire
Barflys Rally 2017
Maryport Blues Festival
Brightonia
I will also add some error-checking into the "Add Event" page to catch this earlier in future