Changed WordPress URL in options and now an error!

Hi ??

Long time lurker- first time poster! I was ‘playing’ with my blog this afternoon and made a silly mistake. Within options i changed teh website URL and discovered an error so quickly changed it back to its original glory.

Sadly- i can no longer access my wp-admin login and the template is all messed up ?? I really have no idea what has happened.

The blog URL is https://www.mountainbikingnewzealand.co.nz

Any help would be very appreciated- as this is driving me bonkers!

THANKS!

paul